what graphic card should i buy?

Hd 5670.

HD5670 is indeed a good chioce but if you have good PSU ( from brands like corsiar, CM, seasonic, gigabyte, tagan etc. ) you can buy a 9800GT 512MB edition card around 5.5k - though it's old it's still packs a powerful punch.

BTW, do post your system details like mobo mdel, cpu, amount of ram and PSU brand and wattage while posting in the future.

^^Will 9800GT outperform HD5670?

^yes.but 9800gt is more power hungry.

But if 1 has a 500W SMPS will it be good enuf to run the card?

^^ 9800GT 1Gb is considerably faster than HD5670 512Mb (as 1Gb version is same). but if you ask for SMPS, everyone will ask same question. whats the brand of that PSU?

I meant for a good brand(corsair,Tagan etc) PSU...Wat I actually wanted to know is tht whether 500W PSU(of course a good 1) will be enuf or does 1 need higher than tht?

^^ will be enough. 9800GT is power hungry but that doesn't mean its extremely power hungry. a good 400-450W will do the job.

^^ yep even a corsair CX400W @ 2.6k or gigabyte superb 460W @ 2.1k will be just enough for it.

BTW, the power consumption of a 9800GT is around 110W-115W.

Is it in idle condition or load?

9800gt is the better choice if you want nvidia 3d. And better drivers.
@ssb
100w on load or full load.

^^Dude u askin me abt tht idle(I take it u 4got to type "idle") or full load?I dunno coz it was posted by topgear!!

I'm telling you that at load the card would take higher power like 100w and above.

Oh!!!got it!!