Giant

2009 Defy 3

I probably don't even have a 100 miles on it yet, but it survived a sprint triathlon (and cut almost four minutes off the 12-mile biking section ... compared to a mountain bike). The frame, fork, and seatpost are good quality and very lightweight. I still need a small adjustment because my medium-small hands have trouble getting a good hold on the brake/shifter levers. Despite the seat, it's fairly comfortable although my hands go numb (as they seem to do on all bikes regardless of comfort).