I currently have a early 11' 13" MBP 2.3 with 4GB ram and 320 HD. Looking to uprgade to a 15" rMBP. Planning on getting base and upgrading RAM to 16. I am in no way going to be using CS6, or big time video editing. Just photo like Apature, a little video, and Parallels. And of course web browsing, and MS Office. Do I need 512, or will 256, be fine? Any other suggestions, won't be gaming, just like the bigger beautiful screen, and size(being so thin). Thx in advance. Oh one more thing, still running Snow Leopard, should I upgrade to ML before putting it on Ebay?