So, I'd need to run OSX with the 6600GT and MOS with the X1950 (will a X1950GT work?) but are either any good in Debian Linux?

Just trying to get a good setup for my new G5 Quad. I have a flashable X1900 as well (for OSX) and better cards like K2000 Quadro (for Linux) but if a PC X1950GT works for MOS and works well for Linux then that would do me?