In any given day, in reading various internet forums and working with customers on their bikes and working on and riding my own bikes, I have a lot of thoughts about bikes, and I frequently think: there's widespread misconception about this topic, and I should set the record straight with a blog post. Of course, sometimes I start writing and get bogged down in the long-winded nuance of the topic, and realize that for all the good info I may (or may not) be disseminating, anybody reading would be quickly put to sleep by the tedium of it all. So I click delete and go to bed, only to repeat the process a few days later. Maybe instead of detailed explanation, I should stick to a concise format, using Surly's famous "Some answers to just about any bike forum post I’ve ever read" or Rivendell's similarly well-read "tips for happy riding" as examples. Truth be told, being thrifty with words is not my strong suit, but here goes, in no particular order:
There are few universal truths in cycling. Every cyclist is unique or has unique priorities in some way or in many ways. What delights one person will be a source of disappointment for others, and vice versa. Anybody who's an absolutist about anything related to cycling needs more experience working in a neighborhood bike shop. Everything I write below is a matter of my opinion based on my own experience and observation. Others disagree, probably, based on experience or priorities that are different than mine.
No bike, no matter how well made, how well reviewed, or how expensive, is going to be perfect or even tolerable for you on any given day. If you own a number of bikes over the years, each one will teach you something. Your next bike might be better in some ways, and worse in other ways, than your current bike. That's why many cyclists own more than one, or even more than five or ten bicycles.
Don't think that boutique level components are significantly better performing than more mundane components. XTR (or Dura-Ace) might cost 5-10x as much as Deore (or Tiagra), but most of that extra cost represents a shiny finish, a few grams of weight, cachet with your buddies, and avoiding the regret of not having purchased "the best". With either top-shelf or entry-level parts, having things clean, lubed, and properly adjusted is far more important to smooth performance than whether or not the part is high-end. Don't buy a used up Dura-Ace derailleur on eBay to replace your mid-level 105 derailleur that still has plenty of life in it.
The really boutique level stuff, made by small production domestic manufacturers who have an impressive attention to detail, is often the best you can buy, and it'll certainly cost you a lot of dough. But even the "best" parts break or have defects sometimes. If your $400 hub shits the bed, it might be at least a month or a year of shipping back and forth and waiting for new parts before the manufacturer can impress you with its famous lifetime warranty. If, on the other hand, you kill a $40 Tiagra hub, which is unlikely, you can walk into any bike shop and be back on the road in a few days for a fraction of what the "best" hub would've set you back.
There are a lot of persistent notions dating to the 1970s "bike boom" (or earlier), that are probably out of date now.
The ongoing reverence for Campagnolo is an example of the previous point. Every time we have to work on a Campy-equipped bike turns into a nightmare of hit-or-miss compatibility issues and/or horrendous design decisions. Nonetheless, that brand seems to maintain an exclusive status because it has a storied history of being standard equipment on all the fanciest bikes 40 years ago.
Not every new cycling innovation improves the cycling experience in a meaningful way, and many justifiably flash in the pan, but some new stuff is genuinely better than what existed before. On balance, good quality bikes made in 2012 work a lot better than similar good quality bikes made in 1975. Plus, we have a helluva lot more variety now.
Pigeonholing various bikes into easily definable categories is about as sensible as pigeonholing various people into easily definable categories. There are so many different varieties of bicycles, and bicyclists, that it makes no sense to parse things so finely, unless you're in the marketing business and trying to define your product to your least knowledgeable consumer. A Surly Long Haul Trucker is a "touring bike", right? Or is it a "commuting bike"? Or a "trail bike"? Or a "Burley-pulling bike"? Our customers use their LHTs for all of the above, and more. If you ride it on roads, I'd say it's a "road bike", but that term has been co-opted by a very limited, but popular niche in the bike universe, and it only confuses people to apply that vague term to other bikes that get ridden on roads. I have a Cross-check, but I don't race 'cross, so calling it a "cross bike" is misleading. I ride it, and all my bikes, in a wide variety of places in a wide variety of situations. What my bikes do has more to do with me than with what category the bike fits into.
Bike fitting is mostly a matter of big adjustments based on factors that are obvious to anyone who has enough experience with bikes. A whole sub-industry of highly technological bike fitting procedures has sprung up on the understandable fear of having a horrible-fitting bike, to which all cyclists can relate. But 95% of fitting can be done by eyeball and addressing specific complaints of the cyclist in question, starting with getting a bike that's approximately the right size. That last 5%, which is done with video cameras and lasers and vector diagrams and computers and other widgetry, is more about squeezing out that last drop of efficiency than it is about alleviating physical discomfort.
The internet is an echo chamber, and there are a lot of people on there making claims with little first-hand experience or with odd agendas. I can't count the number of parts or bikes I've tried that are somewhere between mediocre and absolute garbage, but get rave reviews on the internet forums. It works like this, one person says "Part X is awesome," somewhere on the internet. On this recommendation, 10,000 people buy Part X and have poor to suboptimal results, but since the first guy, and now a growing number of others, said it was awesome, they assume the lackluster results must be a personal failure (or they lack experience to know good from bad), and, rather than admit to being too stupid (they think) to make the damned thing work right, they concur with this new favorable majority opinion, questionable as it may be. Sometimes, especially in the world of "retro" bikes, people get romantic about the way a certain component looks, but that's irrational among technical types, so they delude themselves (and others) into thinking high-performance is the motivation for the glowing recommendation. Bottom line: if you look to the internet for information, try to figure out who is blowing sunshine and who you can trust for the unvarnished truth. And even then you'll have to try stuff yourself, and make mistakes, and learn.
If you spend a lot of money on a bike, you might worry about it more than you would a less grandiose machine. If it's expensive or irreplaceable, you might baby the thing too much. You might only ride it on sunny days, and on smooth roads, and you might be a nervous wreck if you ever have to lock it anywhere. If this is true, then such an excellent bike limits you from the full enjoyment of cycling. Better to have a less precious bike that isn't so limiting. Bikes get dirty and dinged up, and once in awhile they get vandalized or stolen. These are unfortunate facts of bicycling life - you'll enjoy cycling more, I think, if you ride bikes that are nice, but won't make you cry if they get a scratch.
There's a popular notion that bikes are precision machines. Most bikes and components, especially the stuff people rode before the Japanese started sending us their bikes and parts in high volume in the 1980s, are pretty crude if you look close enough.
Your old Peugeot was probably brazed on a Friday afternoon by a guy who'd had three or four glasses of cognac with lunch, and absent-mindedly waved his torch over the lugs on the 18th frame of the day while he contemplated the upcoming weekend with his mademoiselle and more cognac. On every 20th or 50th or 100th frame, he forgot to braze an entire lug or he overheated the BB shell until it was brittle. Sure, it was "handmade", as swanky as that sounds, but on a mass-production basis, not by some old-world craftsman who put his name, and reputation, on every frame. Corners were cut and humans made mistakes. Quality control was variable or non-existent. Your new frame was welded by a robot that didn't care what time of day it was, or get sidetracked or intoxicated. If mistakes get made by the robot, it's on a batch basis, and obvious, and generally corrected before anybody outside the factory knows about it. Sure, the human element has some romance to it, but the robot is more predictable.
No bike is maintenance-free. If you don't enjoy doing bike maintenance, bring it to a good bike shop. It's probably cheaper than you fear, and you'll be thrilled with the results. Maintenance is unavoidable, even if you have an internal gear hub with enclosed belt-drive.
Bikes that are decked out with super fancy parts are not always great bikes. There's a bit of art to it, and spending a fortune only works if it's done well. A super expensive bike with glitzy parts will always get a ton of hits from the bobbleheads on flickr and people reflexively clicking the "like" button on facebook, but a more modest bike that is thoughtfully put together usually fails to generate excitement from anybody except the person who gets to ride it. I like the idea of a really nice bike in disguise.
Sometimes you have a magic ride on a bicycle. Some people are addicted to this, and want to recreate the feeling on every ride. "Chasing the dragon", as drug addicts sometimes call the pursuit of that feeling of the first high, is not going to be fruitful, except once in awhile, when it's least expected, and for no apparent reason that can be duplicated. You can't buy this experience, unfortunately. Sure, it's fun to put new tires or whatever on your bike, but soon, the effect fades and you have no choice but to escalate and buy more new shit for your bike. I see people who have geeked out every aspect of their bikes, down to the cable crimps, in pursuit of that one thing that will make the bike perfect. I hope they're having fun working on the bike, because the magic ride is elusive and has nothing to do with cable crimps.