Good suggestions, everybody.
Adora, I love the artwork, but the text hidden in mouseovers gimmick is driving me nuts. I think it bothers me that it defeats my tendency to skim quickly over text when I read, which may have been the artist's intent, I suppose.
Curses, I'm a huge geek, but I love QC.
xkcd and sinfiest go without saying.
A couple others I really dig lately are
overcompensating which is done by the same guy who used to do When I Grow Up and Wigu, and
A Softer World which is absurd goodness with photos and captions.