If you haven't been yet, you've got to go to Glassbooth.

"glassbooth connects you to the presidential candidate that represents your beliefs the best."

You first mark which issues are most important to you and then you answer questions based on those issues. I'm really impressed with their system.

My results (not surprising):
94% Ron Paul (R)
74% Duncan Hunter (R)
70% Mike Huckabee (R)
68% Fred Thompson (R)
66% Tom Tancredo (R)
60% John McCain (R)
54% Mitt Romney (R)
48% Rudy Giuliani (R)
34% Christopher Dodd (D)
33% Bill Richardson (D)
33% Mike Gravel (D)
30% Dennis Kucinich (D)
30% Barack Obama (D)
29% Joe Biden (D)
28% Hillary Clinton (D)
24% John Edwards (D)