Hi. The command apt-get install gnome works on my unstable box. Gnome 2.6 is the version in unstable. I believe it is also now the version in testing also. If you want to continue running stable, you should checkout the apt-howto package. It explains how to get packages from testing or unstable while running mostly stable packages. I don't find unstable to be all that unstable. You can have problems, but their usually not to bad. The only problems I experience currently are things like clicking on links in evolution doesn't launch the browser. Sometime during the last few months, changes caused the Mozilla and logout buttons to disappear from user's panels. They had no problem adding them back. Btw, I'm totally blind, so I can't use Mozilla or Evolution. These problems effect my sighted friends who use my system, but don't bother me. I only knew about them because it's my computer so I'm the tech support for all users.
Hope this helps. Kenny