On that website you linked, Intel prices are a little high by compared to similar AMD procs. AMD looks like a better option (5-10% more so than in the US).
Phenom II 945, 4GB of DDR3 RAM and an HD 5850. No need to go higher on the graphics card, and unless you do video encoding or 3D rendering no need to get a faster CPU.
It's much more preferable to buy a single card than two slower dual due to poor Crossfire scaling, the fact one card will use less power and produce less noise, and that framerates won't be as smooth due to microstuttering, and also because performance in very new or uncommon games is worse because Crossfire profiles in the driver won't be perfect. In this case I'd recommend against doing two 5750 vs. 5850 since the a 5850 is practically two 5750 anyway (accounting for CF scaling) and 20% more for lower temps/power/etc. would be worth it.
