Ivan Sutherland's Sketchpad:
...And I still need to wait for the next version of Inkscape to support my Bamboo Fun. =(

(Actually, it seems to be more of an issue with the version of GTK+ that the release version of Inkscape uses, but whatever.)
In response to ACWraith
GTK+ 3 is coming! It will probably suck just as bad, but it might have support for a few more things that will benefit the Inkscape crowd...