Debian is a very conservative distro. Ubuntu is based on Debian Unstable, and Testing is more conservative than Unstable. Debian Stable is seldom changed, and very conservative. Once a version goes stable, it only gets bugfixes, seldom any software updates. Sid, or Unstable, is actually a rather stable version, and I prefer it to Wheezy, which is now Testing, because it gets bug fixes faster. YMMV. If you want XFCE Squeeze, you can simply install that, or you can install LMDE, add the XFCE desktop packages, point your sources.list to Squeeze, update, and have it. It's a little longer, but it will work.
BTW, the names of the versions are from the movie Toy Story, and are just a whimsical way to refer to them.
Asus eee-pc 900 w/ 32GB SSD.