I think the best description I ever read (on this board, no doubt) was to think of it as a 3-speed with fine tuning. That is, on the front you have a gear for climbing hills, a gear for tooling the flats, and a gear for those long steady downhills or tail winds.

Then, in the rear, you have fine tuning gears. Just stick to the 4-5 gears in back that match your front gear.

Around my house, I have short hills and flats, but rarely see long downhills (we're rolling). So I spend most of my time in the middle and the middle of the back. When I travel, I get to use my other gears and remember why I have a triple.