About the processor I'm sure ill put in some use for what ever else i do with my computer as i used a lot and not only for games, so I'm happy to pay the extra cash for the X58/i7.
As for the GPU i have been debating between the 470 and the 5850 for some time, and im not yet 100% on what to get.
As for the other elements is what i kinda have found that works and to safe money where i can.
PSU... I would recommend the Corsair CMPSU-750TX instead. This PSU will give you better upgrade path with running the 5850's in Crossfire. The OCZ is nice but won't truly cut it for a Crossfire setup.
DVD: You have an IDE selected and you will want a SATA for better cable management.
Hard Drive: The WD 640GB Black was great in it's day but has been passed by the Samsung Spinpoint F3 & Seagate 7200.12 drives (500GB & 1TB). I would recommend one of those drives over the WD 640GB Black.