Ok, anything about medium in Starcraft 2 will require 512 mb vram which is the i7 package. Running Starcraft 2 on recommended settings, 95% high peaks cpu usage at 158% while only peaking disk activity 27mb read. Dont buy an SSD, upgrade to 8gb ram from 3rd party and spend the money on the 2.66 i7 and a 7200rpm apple or momentus xt hybrid. My Momentus XT loads Starcraft 2 in 5 seconds the first time, 2 the second time and if I played it regularly it would only be faster
I`m glad someone with a bit more gaming knowledge stepped in at this point, I have no clue as to what specs are required for gaming, really not my area anymore