Cool site, cool idea. I've always been a ban of the neutral color schemes with a picture of something relating to the topic used to inject some excitement with color.
The text seems to be a bit on the large side.
The top navigation in both IE and Firefox on Vista with default settings gets broken into two lines.
In Firefox, "Login/Register" is on the second line, and is overlapping the picture making it hard to read.
In IE Login/Register gets cut in half, and it says "Login/Regis" on the first line, and "ter" on the second.