50-34 x 13-14-15-16-17-18-19-21-23 although I have an in-shape weight under 150 pounds. With an extra 30+ pounds of fat I'll swap it for for 50-39-28 or 26 x 13-14-15-16-17-18-19-21-23-26 after wearing out the current chain (cassette should be about shot at that time, rear derailleur is already worn and getting sloppy, first generation ergo small parts have been discontinued, it's a good time to switch to 10 speeds) since there are mountains I want to climb while still heavy and without another 5,000 hard miles in my legs.

I added the 23 cog on the end when Campagnolo discontinued my preferred 8 speed cassette of 13-21 and switched from a 50-40-30 triple after wearing out my big ring and realizing 34x23 was the same low gear as 30x21.

While the compact has the same range as my old triple (which I picked to get tight spacing for plains rides east and the Rocky Mountains west without changing cassettes or wheels 3-4 times a week), there's only one overlapping gear that's not fully cross-chained (50x21 and 34x14) so there are hill/wind/fatigue/recovery day combinations that result in a lot of double shifting where each front shift goes with a five cog change in back. The chain's also a lot noisier in some situations because instead of riding 40x17 in the middle of the cassette I'm in 50x21 or 34x14 that's nearly at the end.

Hills destroy you because your power to weight ratio is too low. Increase your power (get a training plan which involves hard intervals and stick to it, or at least mix sweet spot rides with recovery days in each micro-cycle) and/or loose weight.

Low cadence drills will get you producing the same power when you're running out of gears (you should be able to manage the same power at 50 and 100 RPM) but you still need to increase your power.

Trying to make do with higher gears will mean you fatigue sooner on hills and end up with a lower sustainable training load and fitness than if you used appropriate gearing for your current weight and fitness.

If I wanted those extreme gears I'd opt for 53-39-24 x 12-13-14-15-16-17-18-29-21-23 or 53-39-26 x 12-13-14-15-16-17-19-21-23-25 instead since the close spacing feels a lot better on flat ground.

It's simple arithmetic - there's a limit to the power you can produce at various durations, that power produces speeds which are inversely proportional to your weight and decreasing with the grade, and you need low enough gears that the resulting cadence isn't so low you have unacceptable fatigue.

Power given speed calculator. Put your numbers in to estimate power. The estimate will be more accurate if it comes from a steeper grade where aerodynamics are a smaller component. The drag coefficient is low - Gibertini and Grassi measured .760 for a cyclist riding on the brake hoods. I got rolling resistance of .005 when playing with my power meter and Golden Cheetah's aerolab implementing Chung's virtual elevation model.

http://www.analyticcycling.com/ForcesPower_Page.html
Put your numbers in and the steepest slope you plan on climbing (this is easy to find now that we have on-line sources like mapmyride.com and ridewithgps.com)

http://www.analyticcycling.com/ForcesSpeed_Page.html
Then take the speed in meters per second, multiply by 60 seconds, and divide by roll out (about 3.14 * (622 (for 700c; use your ISO bead seat diameter for other sorts of bikes) + 2 x tire width in mm) / 1000) to get tire revolutions per minute. Divide by the lowest cadence you want to run and you have a gear ratio that will keep you happy.