For people using Debian Unstable be aware that it's undergoing a huge transition/upgrade period. There are some major things that are changing.
X.org is now entering Debian.. 6.8.2. Also they are switching the C++ ABI from Gcc3 to Gcc4
Both of these things are causing large amounts of packages to be non-upgradable, or that when you upgrade one package it will try to unstall several packages.