the only difference between the 930 and the 950 is the factory clock speed. other than that they are identical. if you arent going to be overclocking ( which is foolish ) go with the 950, if you are overclocking i say go with the 930 because its a prooven champ at overclocking. some people would say go with the 950 because its supposedly binned better and could get a better overclock, and they are right, but there isnt any real evidence that they are binned any better so the chances of a better overclock witha 950 over a 930 or undetermined and the 930 has proven its self.
THe radeon 58xx series are great cards! if you are still wanting multi monitor support then the eyefinity cards are your only choices.
the regualar edition 5870 can support 3 monitors and the eyefinity edition cards can do 6 monitors.
EDIT:
you posted the same link for your Powersupply and your motherboard
EDIT EDIT: id recommend going with a regular hdd and not spending the premium price for the 6/gig second