Sketching/drawing on the ipad?

[zapadapa]

Anyone have any good suggestions for a nice and handy app to do sketching on the ipad?

I've tried sketchbookX and inkflow and some others, but those really didn't do the trick for me..I'd like to have a bit more brushes and the ability to zoom in and out pretty freely (detials are a bit hard to do without that)

Cheers!