For what you got the build is fine. Poster number 2 suggests 2 cards when you can only run 1. Also, the 5850 is 10 tons better than those 2 in Xfire. The numbers might be similar but the actual performance isn't.
Can't comment on the drive because I never used one of those. Right now I get 500gb Samsungs for most machines.
Do you believe that?
Go around and check samoe benchmarks before you post your so called opinions