I don't really see the need for the striker extreme. If you want SLI, I suppose its not a bad choice, although striker extreme + 4GB RAM is not a happy pairing.
so, my suggestions
-Mobo. For SLI, consider that none of the 680i boards support the new 45nm processors, so you won't be able to upgrade in future. Also the EVGA NF-680i might be a better choice. Otherwise there is the new 780i with PCIe2.0 and 45nm compatibility. If you don't care about SLI, get a P35 board (e.g. GA-P35-DS3R, Abit IP35 or Asus P5k), or an X38 board (Asus P5E, Maximus formula).
-There are better CPU HSFs. maybe a Tuniq tower 120.