http://glassbooth.org/ Pretty cool, you plug in how much you care about various political issues and where your stance falls, and it gives you how closely the candidates align with your views.
FWIW: I clocked in with 91% agreement with Gravel, 85% Kucinich, 82% Obama and down from there. Kinda scared that the highest match on the Republican side of the fence was Thompson at 50% - he frightens me when I think of him as Commander in Chief.