The sweetest riding bike I've ever owned: A mid-eighties 24" Trek 560 Pro Series, 531 tubing with beautiful window lugs (bottom bracket shell and seat lug have the "Trek" name cast into them), with full Shimano 600 SIS group, including pedals, headset and seatpost.
Bought this one new and have kept it mostly original since then, except for the rims (the stock Matrix rims were replaced with Mavic MA2), the 600 170mm Biopace crank/rings were switched for a longer 177.5 Dura Ace crank with round rings, the orignal short stem and narrow bars were replaced with properly-sized Cinelli stuff, the old-style Shimano cleat pedals with straps were replaced with the more current Shimano Look compatible pedals and the seat has been replaced so many times I can't recall what it came with. Back then they would spec bikes with shorter crank arms, stems and other stuff, no matter how large the frame.
The thing always did fit me like a glove, it rides like a dream (I prefer it over anything else I own) and the bike still looks great (fire engine red with yellow head tube and yellow accents and decals). The original 600 group was/is great stuff: the derailleurs and 6-speed downtube shifters still look and work like new, the 600 brakes and levers are gorgeous and the 600 hubs have been rebuilt dozens of times and still spin smooth as silk. They just don't make them like they used to.