Never heard of 6850 and I gues a single 4850 will last at least 3 yrs for my standards
Well as of now final pc specs:
e8400 with after-market cooler to 3.4ghz
sapphire 4850 dual slot cooling
p45 pq pro http://www.newegg.com/Product/Product.aspx?Item=N82E168...
ddr2 pc6400 4-4-4-12 ram
get a p45 with pci 2.0...
and don't go crossfire
as eklipz sad, there will be a better card out... for about the same price...
Dual card solutions are a waste of money... unless your being sponsored like liquid... and gets lots of equipment free of charge... than dual and even triple card solutions are great
EDIT: what he means by 6850 is the mid range card TWO generations after the 4850
If you actually look at any other game provided in the tweaktown example other than crysis, crossfire doesn't even kick on on the p45 they use (the benchmarks are the same as a single card), if you look at say 3d mark vantage or UTIII the differences are minor at most and in some situations (even in tweaktown's benchmarks) the p5q comes out on top. Only if you game at the highest resilutions (ie. 2500 1600) will a 4850 get bottlenecked much. Remeber PCIe2.0 8x is the same as PCIe1.0 16x. I have 4850 cf on a p5q deluxe and have no resentment for my decision. also the P45 is a much better chipset and you will be able to do so much more with it. (does p5n 750 even have raid support?) And since the op will have just a single card for a while he should get a 4850 which is a much better card. You will only need all 16lanes of PCI2.0 if you get a faster ati card like a 4870 or a 4870x2 in cf which would show significant bottleneck. Or if all you play is crisis.