Appearance, I'm pretty happy with it.
Although I don't really like webpages that are centred, leaving the left and right empty, this was done to ensure that old monitors with low resolution could view properly.
If you want to improve it, you could read up on fluidity in CSS. This is one of the most flexible websites in terms of styling. But not so easy to write as parts could overflow and some cross-browser compatibility issue.
Here's one example which I liked a lot.
http://www.wpdiva.com/themes/25/accidental-greyscale.html 