Wow! It looks like triple-fever is sweeping the forum... at least this thread. Those considering a triple should run the numbers through Sheldon Brown's Gear Calculator or something similar. I have a standard Shimano Ultegra triple on my commuter bike: 30/39/52 crank and 12-27 cassette. On my road bike, I have a SRAM compact double: 34/50 crank and 11-28 cassette. The lowest gears are pretty similar with each setup (30.0 gear-inches vs 32.8 gear-inches). I haven't found a hill yet that I could climb with the triple but not with the compact double.

In my mind, a road triple only makes sense if you're going to swap the largest and smallest chainrings for lower gearing (ex: 30/39/52 -> 26/39/48) or if you're super-sensitive to gear spacing and strong enough to run a tight-ratio racing cassette (ex: 30/39/52 + 11-25 cassette gives a 32.4 gear-inch granny). If you already own a bike equipped with a double crank and an indexed shifting system (STI, DoubleTap) a compact double crank and wide-range (11-28, 11-32) cassette, perhaps combined with some additional training, are probably more cost effective than switching to a triple...