As a kid, and even in my teens, I always wrote by hand. But now just the thought of having nothing but pen and paper gives me writer's block! This is partly because I have either severe carpal tunnel syndrome, or some form of early arthritis (not sure which, as I haven't been officially diagnosed) but writing by hand is now physically painful for me. I can only do so for very short spurts at a time.
I love the freedom that the keyboard allows me, and the ease with which I can edit (another liberating factor) and, besides, there's just something about the immediate satisfaction of being able to see your work in print form, before your very eyes.
I am very much aware that Shakespeare, Milton, Keats, etc etc created great art with pens and quills, but as one of my favorite arguments goes, the only reason those guys didn't use computers was because they didn't have them!
We do, and I'm grateful for it.