I recently picked up this awesome realistic media art program called ArtRage (from New Zealand outfit Ambient Design)

http://www.ambientdesign.com/

It's like a modern day spin on the old Fractal Design Painter type application, and works really nicely with the Touchsmart screen thanks to easy to touch menus and palettes. While it doesn't support multi-touch or detect pressure (I don't think there's really a way to do this with the Touchsmart's IR based screen), it's still great fun to finger paint with oils, charcoals, crayons and spraypaint.

At just $25 retail, HP should consider OEM-ing this application with the system. It's really outstanding for showing off the touch screen, and tons of fun.