to be happy with the catalyst it needs a) a matching X-Server and b) a matching kernel. Booth you will find in stable (or Arch ..). Beside of these issues its a good idea to learn to patch and build booth Server and/or drivers. That was my start with ubuntu and debian-packaging. It's a little bit steep learning curve, but it is worth it. (OK, one can think about using intel or nvidia right from the start :twisted: )
I see -- so, with our frequent kernel updates in sid, we would have to rebuild our X-server and catalyst packages for every new kernel (or pin our kernel for a few months).
The first computer that I tried Ubuntu on had an ATI card in it, and the difficulties that I had configuring a /etc/X11/xorg.conf file were so painful that I nearly gave up the project. (Of course I am now very glad that I stayed with it.) But ever since that terrible experience, I have built my computers with Nvidia cards (or bought them with Intel chips). There are too many better ways to spend time in life, than wrestling with such difficulties when you have another choice.
Wow -- this thread has become very philosophical -- I hope the OP is not offended!