So i might be interested in getting a PS3 mainly for its Blu Ray capabilities. Whats the difference in the difference models. I'm on the official Sony PS3 site and its lists 120gb, 160gb, 250gb, and 320gb. I'm just guessing but is the 160 a successor to the 120 and same with the 250 and 320? If thats the case, was it just a very minor spec bump or was there other features added?