I think until you're at a certain point in your riding "career", those granny gears help a lot! And yes, those gears in the back make a difference. Mountain bikes won't have as many "zoom" gears, but they have larger, lower gears for climbing. Road bikes that come with a double (two chainrings) (like your Madone) will have somewhat lower gears in back to help compensate for the loss of the small chainring that comes on a triple. It's hard to find a triple on the more expensive bikes, presumably because there are more issues in shifting (and maybe manufacturers assume that by the time you're buying one of those, you won't need the granny gear? .

I live somewhere hilly, so if I get the opportunity to buy a road bike with a triple on it, I'm doing it!

You might want to try riding your Madone in lower gears than you seem to be. It'll be easier on your knees too.