I'm thinking of buying a 13in MBP. (I know that new ones are around the corner, but that's NOT my question -- I have reasons for wanting to buy one now.) The two most "power hungry" apps I'll be running are Lightroom and Parallels, so that I can use Windows 7. I am deciding between getting the 2.26 GHZ 13in MBP with a 6 GB RAM upgrade, or the 2.53 GHz 13in MBP with the standard 4 GB RAM. I would like for pictures to open more quickly in Lightroom than they do now (on my 2 year old MBP with 2.4HZz processor and 2 GB RAM...), and I want to be sure that I can run Windows using Parallels, without any lags. Which of the two systems would you advise?