My approach has been to shop around for a good LBS and then make nice with the owner and wrenches. There's a lot of cheap, durable, no-name parts out there that I wouldn't get on my bike unless my two LBS's had found it for me. I'm thinking esp. cranks; stems; saddles; handlebars; levers; low-end Shimano derailleurs, bottom brackets and hubs. My current bike has a bunch of cheap stuff on it, that kept the price down, and if I want to experiment with size, won't cause me think twice. And, I got it built up the way I wanted without spending what I would have on a new, already outfitted bike.