On my CAAD 10 I had a compact 50/34 with a 12-27. I killed it on the climbs, only being defeated on Fargo Street and Eldred Street in Los Angeles. These two go up to 30+ degrees. Sadly, that bike was stripped by thieves.
I have more or less pieced together my RB-1 53/39 with a seven speed freewheel 14-28, and 12-28 spread on another wheel with a cassette. In its previous STI equipped version, it had 50/38 to 12/27. I did pretty well on climbs, and suffered on climbs in the mid-high 20's. I have yet to go climbing, but I am looking forward to it, as that's what I enjoy doing.
Related Threadjack alert: Is it possible to slap on a mountain derailleur on the back with a 53/39 in the front? I'd like to go to 30 or 32.