4870 x2 or another card

hello
i'm going to build a buget gaming system.
i was looking around the web and i saw that the 4870 x2 is a pretty decent card.
somebody i know is going to sell one for 90€ and here is my question should i go for it or should i get another card that is better then it?
system specs:
corsair vengeance ddr3 1600mhz 8gb kit 48.99€
sandisk extreme ssd 120gb 98.99€
Asrock 970 Extreme3, sAM3+ 66.99€
Cooler Master K-380 with Window 42.99€
OCZ ModXStream Pro 700WATT 79.99€
AMD Phenom II X4 965 BE, sAM3 85.99€
total = 423,94€
(i think the case would be big enough for it but if not then i will pick another one)
the maximum i want to spend is 600€
with the 4870x2 it would be about 510€
this is just an buget gaming sytem so noyhing really fancy.
the games that are going to be played on this sytem are: bf3, bf2 bad company, need for speed most wanted, cysis 1 and 2 (maybe 3 wouldn't know) just cause, ...
it just needs to be playable at medium high at 1080p or 720p with AA
thanks for the help
 
the 7870 is out of budget cause the ceapest one is 220€
i think i'm going with the sapphire hd 7850 2gb that is 179,99 (http://www.mycom.be/computer-1/componenten/videokaart/sapphire-radeon-hd7850-2gb.html?___SID=U) or would i better get an 10€ cheaper 1 gb card (http://www.mycom.be/computer-1/componenten/videokaart/sapphire-radeon-hd7850-1gb.html?___SID=U) or just better craossfire 2 7770 (95 each)?
 
There are very few games where the difference between the 1GB/2GB HD7850s will impact your game play. They are also notorious over-clockers, and could easily reach HD7870 performance levels

(that could save you and your friend some €)