What in the world are you using your phone for? I'm not saying you're a liar or anything but I've honestly never had any problems with any of my 4 iterations and they've all been heavily used. I've also not heard of this problem from any of the dozens of iphone users I know.
Well the first five 3gs's I had all had to be replaced (thanks Apple) due to faulty buttons. I've replaced buttons on two 4's.
Guess they don't like me and It's a chore, but I just use them normally.