A while back I posted a collection of 12+ free photoblog themes for Wordpress and Blogger. Like I said at the time, with the multitude of free themes out there, that collection barely scrapes the surface of all the posibilities you could be considering.
Here is a new resource for 'I want to look good online' needs - Graph Paper Press. Their work is increasingly focused towards visual artists. While you can sign up for their service, several of the themes they offer are free