cdr -- I ride a Rival setup 53/39 and there is absolutely no danger at present of me needing to go bigger than 53/11 (got the 11-25 in back ;-) I weigh 145 and FTP is in the area of 240w at this time. My TT race cadence runs between 90-100 RPM. I have yet to race a TT that requires me to drop down to the small ring, but I know that is coming in the future. I expect to learn a lot about my strengths this season as I race quite a bit more.

coachboyd -- good point re: weight over the wheel. This year I switched out my Profile Design T2 bars to a cleaner Deda Parabolica set, upturned at the ends to reduce my frontal exposure. Balance over the front feels good so far.