I think the configuration that allows for the best temperature dispersal would be fans in the front pulling in air and then fans in the back and top of the case pushing air out. You can set up your CPU heatsink fans accordingly to move with your air flow. And yes, GPU's vary in what fan method...
You could go with the setup I am currently aiming for.. I bought one 5770 awhile ago that performs admirably by its lonesome at 1000mhz core and 1420mhz Ram. I will eventually pick up a second 5770 and crossfire.. A lot of reviews have shown that xfired 5770's can hold their own next to a 5850.
I would have to agree. Fermi will support DX11 and newer games will eventually as well. The price you pay for Fermi will probably be ridiculous but it will definitely be an improvement from what you have... I would personally snag a high end ati card once fermi released... because the prices...
I agree with Naieve,
Fermi is near release.. and the price on the 5970 right now is pretty substantial. If it were me, I would wait a month or so until the price went down...