This short vid shows what nice little (yet completely to die for) additional stuff DICE has made for the PC release of BF:BC2
My current favorite is the UI, which looks much smoother than the previous UIs in Battlefield games. Also, another favorite of mine is the game's ability to use DX11 shaders and stuff and the Horizon Based Aim Declussion? (HBAD for short, though I'm not really sure what he said for the D in HBAD).
Believe it or not but I can max this game out with a Nvidia 9800gt/E8400 OC/3GB RAM.
So not that heavy at all. Especially if you come to think of the fact that this game is designed for Quad-core.