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