I was just looking at [MENTION=399166]thumpism[/MENTION] 's Schwinn Cimarron- it's not a stock build, not a modern build- but it's very beautifully classically put together. Yes, some of the components are from a few years earlier than the bike, so technically they don't "go with" the frame- but they're perfect on there.
I have a "thing" with Suntour MTB derailleurs. To me, the XC Pro and XC Comp derailleurs are the perfect combination of "business" and gracefulness- I don't see it as "wrong" being on most any bike. However, each of my 3 touring bikes are from 1984 and 1985- but I still outfitted them with derailleurs from 90-94. Yes, it's "wrong" and I'm sure there's a purist that's gritting his teeth because of how I've "wrecked" or disrespected the bike...
However, the only time someone's ever mentioned that I made a silly choice in my build was using the tri-color stuff on my 1986 Trek 400 Elance:
What are some of the bikes that have components that don't belong on there that make that bike perfect?