Thinking about upgrading from a 7600 GT soon. Have a few questions.

Hello everybody,

I am going to upgrade my graphics card for my PC but I have a few questions,

First off, my budget is $150 (no higher) and I am wondering what graphics card I should get. I seem to have missed the $125 4870 deal so I am looking at either an HD 4850 or a GTS 250.

My specs
400W Power Supply with a 6 pin PCI-E power connector (I am wondering if it will support a new Graphics Card)
Core 2 Duo E6400
4 GR DDR2 800 RAM
GeForce 7600 GT

I am hoping to run Fedora Core 12 with Windows XP seamlessly virtualized on top. I work with both linux based OSes and Windows and I don't like to reboot quite so often.

My hope is that 3D acceleration will work well under virtualization and I will be able to game with it; if not, I can just reboot. I would prefer not to reboot just to game though.

Only going to play games like Team Fortress 2, Half-Life series, source mods, etc. I rarely game anymore though.

I am also looking into GPGPU programming on a linux platform. I was reluctant at first to go with ATI for this reason but Brook+ doesn't seem to hard to learn since it is C like. My question is would one brand of card be better than the other as far as GPGPUs go (better hardware, better compiler, easier to program etc.)?

And I MAY 3D model in my virtualized XP platform, not likely though.

Another question is, should I wait for Black Friday to come along? Or say I go with NVidia, should I wait until the 300 series comes out? Should I wait for anything at all?

My preferred company is Newegg.

If you have any other good card suggestions for these purposes then please mention them.