I last bought a new bike in 1996 when I had nice Campagnolo components hung on a Litespeed titanium frame.
The fork, headset, stem, bars, brakes, and hubs have yet to wear out and remain original (to be pedantic that's not quite true - the brake return springs both wore out and failed due to fatigue although Campagnolo sells those separately so I didn't need to replace the brakes). The spokes and most of the nipples also date back to the 1990s but got replaced with the original rims (I did reuse them on the subsequent replacements). I also replaced the freehubs with 9 speed parts on that wheelset and another I use for cyclocross tires on snow days when I wore out my last 13-21 8 speed cassette and found Campagnolo had discontinued the combination. The seat post didn't wear out, but got replaced with a round one so I could use a post mounted rack.
If the economy improves and kids progress beyond their odyssey years I'll probably get a custom titanium frame welded with chain stays a bit longer to better accommodate a pannier commuting, long reach or cantilever brakes to clear fenders for more pleasant rides in the rain, lower bottom bracket than a cross frame, and travel couplers . I suppose that'd be like George Washington's axe which has had both handle and head replaced.
Last edited by Drew Eckhardt; 10-02-12 at 11:27 AM.