Jonathan Coulton's music is awesome. "Code Monkey" and "Re: Your Brains" are simply great. The inappropriate for all ages "First of May" is another favorite of mine. :)
On the nerd front, it's all Creative Commons licensed, so I peer-to-peer'd a bunch of his .mp3's, donated $10 by buying a monkey on his site, and will donate more as I listen to more of his music. I predict he'll make more money from me than he ever would have just selling traditional albums.