Here is a cool little sketch/paint program by ArtRage..
give it a look see.. pretty fun..
The paintbrush is pretty natural...
"Live each day like you will die tommorow, and dream like you will live forever..."
Pretty cool... nice little free program..
I like how the tool panels disappear if you're in the middle of a stroke that goes near them.
And it's free.. so that's a good thing.