I've done the climbs you mention and more with a 50x34 double on the front and a 32-11 cassette on the rear (10 sp). I've never wanted for a lower gear range but will run out of gearing at the other end when going downhill and wanting to go faster than about 35-40MPH (which is not often ). You also give up granularity between gears with a wide-range cassette but again it's never really been an issue for me. Two vs. three on the front is one less combination of gears to not worry about.