I like a 53-39 for anything up to a moderate climb, a compact 50-34 for sustained climbs where you run into inclines >8%. Then again, I climb like a round boulder, so YMMV.

If you are really uncertain you might want to get a SRAM gruppo, as they use the same FD & RD for either crank, unlike shimano, which uses a different FD and a long cage RD for compact. That means if you decide to change your cranks you don't have to change half your gear train at the same time.