Yep, I use all 10.
On a related note, I found it very annoying when I got my Microsoft Natural Elite keyboard. Being an ergonomic keyboard, the keyboard was split into two halves. It was okay for every key except the "Y" key, which I always press with my left index finger. (I do more typing with my left hand than my right, even though I'm right handed.) On this keyboard, though, the "Y" key is on the right-hand side. So I'd be typing along, and all of a sudden my left hand would jump to hit the "Y" key on the other side!! I have finally trained myself to do it with my right hand, but it slowed me down there for quite some time.
Nick