I've just launched a redesign of my web site, which makes it the fifth version, if I recall correctly.
It's based on a simple grid with six columns of 100 pixels width and 20 pixels in between. Those are pretty much the same dimensions as I used for UIScape.com, and I've found them to work quite well: narrow enough to allow some flexibility and wide enough for most content. However, it only works if you have a very narrow sidebar. (With UIScape, I had to cheat by adding another 20 pixels on the right.)
I used to have a strange aversion to using non-white backgrounds, but this time I had a very particular look in mind, so I decided to just go for it. I was going to at least use PNGs with transparency for all the graphics, but too many people still use bloody Internet Explorer 6, so the background colour is fixed in the images.