[Damn, I thought I was replying to reply to list - why is this list manager broken?]
Site 1 is too sterile; too simple.
Site 2 is the cleanest with the most distinctive design but I'm not so sure about the background unless it does something useful. It could grow on me though. The site certainly scales well.
Site 3 has a a horrible choice of colors. Kind of too Christmasy. Red text on red background? Am I supposed to be able read that without squinting. Low contrast text-background combinations are bad, bad, bad.
Site 4 is the easiest to read and, along with site 2, very uncluttered and easy to scan visually. A Website's first priority is to be informative, not just be an art project. If I can't read it, I won't read it. I can read this site easily without work. This site is also just good art.
Site 5 is very clean also. It looks like so many other sites and so doesn't really stand out.
I'll have to go with 4 as the clear choice for first place, with 2 as a close second, and 5 coming in third.