A bust of a grizzled old alien I drew up in Sculptris.

He's pretty high poly (roughly 100k triangles), so he'll be a pretty good demonstration of your printer's quality.

And if your printer messes up near the end (like in my first attempt), he makes a pretty nice container for your tools!

I've attached the Sculptris file in case you want to make some changes of your own. The base isn't flattened in this version.