Like I mentioned in the OP, I already tried that with no avail. What did end up working for me was an S-video out, I just have MASSIVE clipping/tearing on the edges. The DVI to VGA didn't work no matter what button I pushed. I'll be upgrading soon to a DVI to HDMI, and when I do that we'll see if I have any problems.
The 8600 card needs a lot of manual config at the moment as the AVWizard does not handle the config correctly. It is possible to get them working with some manual config and there are several threads here where people have done that.
However I would suggest that you simply get yourself a 6200TC or a 7300 card as these work out of the box using the nVidia driver that ships in LinuxMCE-0710.
All the best