Withe three display, Metro 2033 will be the most demanding game, and you will need GTX 680 or HD 7970, which are way out of your budget. Or GTX 560 ti SLI, still out of budget albeit a little bit lower. Either you need to increase your budget, or play on 1080p. Another option is to wait until GTX 670 launch, although I'm not sure 670's performance on three displays.
3rd: Wait for GTX670ti and GTX670. They should be GK104 gpus with lesser cuda cores, 7/8 SMX (1344 cores) enabled and 6/8 SMX (1152 cores) enabled, which there will be $349-$399 and lower for the 6/8SMX (maybe around $300).
With ur budget range, u can only get mid range cards , As u wont wait for any new release, u have few limited options either the mid range 500 series nvdia cards or the newer amd 6000 cards. Metro 2033 is still hard on both nvidia and amd's top end cards. And u may play with triple monitor setting . Am really curious how u will attain that.
funny thing that u say u r going to buy two card 200 eack. If we sum up it is $400. As helltech said u can get one 7950 + 550 watts ups, can u get any better then this. This is the best deal u can get. All good mid range cards are above $200. Beside never prefer any brand over other. U choice should be best performance respect to ur price range.
ok got that. 200 now and 200 later. do get the new amd 7000 series card that is within ur budget range as suggested by Memnarchon if u r in real hurry. The oem release of the new nvidia looks pretty interesting. Hope Nvidia also releases info about their consumer counter-part within 3 weeks . Then will have a bit more choices. Sometime it pays to wait a bit longer.
So, the 7850/570 for crossfire/sli. But If I wait for the oem release of the new nvidia, what if by the time of that release, I've gotten enough for a 7950, would I be better off with the 7950 at that time?
OEM release are only for vendors i.e those cards that come with pre-built systems ok. Two 7850 in cross fire will give u more perfomance then single 7950 but will cost u more money (your $200 + $200 formula) and will consume more current. 1st, u prefer AMD over Nvidia. So ur best choice is 7950 or 7850. But read this review of ur card http://www.tomshardware.com/reviews/radeon-hd-7870-revi....