I'm definitely in the "uberclyde" category. I started at 385#, now at 310#. Still got about another 100lbs to go.
The only problems related to my weight I've ever had with bikes were the seat-post collar. I had some problems on my aluminum-frame Trek 6700, since I couldn't tighten the collar enough to prevent slipping until I replaced the bolt with a steel bolt and a nut. My current daily ride is a Redline 925, which I replaced the seat collar with a Surly Constrictor ($15), and haven't had a single problem with slipping since.