Which is the best video card for my PC

Hey guys, i have a system without a video card, and I would like to buy a high end video card which suits my system and my needs best.
My system:
Asrock P45XE
Intel Core2quad q6600 2.4ghz
2x2gb kingston 1066mhz
Fortron Epsilon Plus 80 800w Atx 2.3
the rest of the parts don't matter, oh and I have very good airflow in my case:
1 intake fan, 2 exhaust fans, replaced CPU fan(asus silent knight al), 1 side fan, 1 PSU fan.
I want to use my computer for gaming mostly, so which video card would you recommend me, i'm looking for something in the price range between the GTX260 and the GTX275 from nvidia( it doesn't have to be a nvidia, it can also be an ati), about 200-300$.
So, which card would be best for my configuration?

Thanks.

I cannot find this card at my it supplier, the latest from ati i can find is 4890

^+1

It's worth waiting for this card. Unless you have the older cards and want to crossfire or SLI, I would stick with the new gen cards.

I'll ask about it, i'm gaming on an LG 22'' wide, 1680x1050.
I can buy the GTX 285 TOP at a discount price, the same as the GTX 275, is the 5850 or the 5870 from ati better?
I've heard that ATI has some issues with drivers, that it cannot get all out of the video card.

i think 5870 is better. it has dx11 support. but if you don't really care just pick the one you like

I've also heard that ATI can't mach the Nvidia physX technology, even though they get better performance out of cards, they can't "put it on the ground" like they say with cars... oh and also the ati has only 256 bits, the nvidia has 512, are directx11 and opengl 3.2 technologies enough to outperform the gtx285?

what does physx actually do? i want to make the right choice

It puts some physics calculations into the GPU, as opposed to the CPU. breaking wood, flames, glass, water, anything that moves on screen in relation to your actions can be run through PhysX. The end result is often more realistic environment destruction. Personally, I haven't been ultra impressed by PhysX, thus why I feel it is overrated. IMO. it doesn't appear to make enough of a difference to warrant the worse price/performance ratio of buying Nvidia cards just for PhysX.

To each their own, it may be your thing, just explaining why I don't do backflips over it, heh.

i've found some benchmarks, 5870 looks really really good: http://forums.extremeoverclocking. [...] ?p=3527612