To stop myself from endlessly wasting time browsing computer hardware I have actually bought a new computer.
Contrary to my initial plans I have gone for G33 instead of G965, since according to all benchmarks I could find the latter is not a lot faster (just a little bit, both are dog slow compared to almost any separate card). This allowed me to use a board with DVI on board and use one of the cheaper E6x50 CPUs (FSB 1333).
I am still running mainly etch, just with a newer kernel from backports.org and Holger's Xorg backport. Everything sees to work.