thanks guys u have been incredibly helpful. just have to narrow it down to either 4870 or the gtx 260. are either better than the other? or roughly the same?

They are more or less the same in terms of raw power (some games will favour one architecture or the other) but slight edge goes to 260 due to lower power consumption at idle, cuda and physx support (it is marginal but it'sbetter to have it than not) ,896 MBs of ram which sometimes gives nice edge for games with huge textures and more quiet cooler.

But you will be happy with either of those.

PS. Just make sure you get one of the core 216 versions of gtx 260.

i recommend waiting for a few months since the next DX11 cards are due along with price cuts for cpus

@ phnguyen: oh really? but will that make as big difference? and those cards will probably be very expensive?

Go for the HD 4870, its got direct 3d 10.1 so it will benefit from the release of direct 3d 11 by as much as 20% in some cases and it has a tessellation engine which IIRC is direct3d 11 compliant. I think it would be more future proofed, but get the 1GB version.

^this

If you want to run it on high settings, it is safe to say you will have to spend atleast $1000 to achieve that.

@squilliam: yeah that one sounds good if it can run dx11. dont want my card to become useless quickly. ok ill go with that card. is there anything i should do to change from the nvidia 250 when i get the 4870. Do i have to remove all the nvidia software and stuff? also, is there something similar to ntune for ati cards for overclocking?

thats way to old to play that!!!

Theres no point in replacing a GTS250 with an HD 4870, theres simply very little point to do that. They perform too similarly it would be wasted money.

The HD 4870 is the most forward compatible card in its class on the market today, but its still only a direct x 10.1+ card. Its not a fully direct x 11 compatible card. The new cards in this range will be coming in less than 6 months.

ATI overdrive or Rivatuner are two equivelents to Nvidia overdrive, they both work really well, ATI overdrive is easier and it has built in limits to prevent you from taking things a bit too far. Rivatuner is for advanced users.

If you can afford to wait, you could simply try to get a Windows 7 + Direct x 11 compatible computer at the same time. You'd get the most future proofed and up to date system and since both are coming in a matter of months, not years it may be worth waiting for.

I'm sure it's going to be cheaper and better than your current build.  DX11 is going to replace 10.1, so if you want to get it now, and then upgrade, then yeah, it's going to be very less expensive.