I really would like to get the cheaper, lighter, smaller, more portable 13" if at all possible. However, I need it to smoothly run Final Cut Express (I do some video editing for work) and Logic Express (I'm a full time musician). I travel a lot with my computer and my current 15" 2.16GHZ MBP has always been a bit bulky and heavy, and lags a bit when using Final Cut. Will I get smooth performance running FCE and LE with the 13", and will it be a capable computer (keep up with updated software) for the next 4 years or so? I'd probably max out the RAM and maybe get a faster processor if I was to settle on the 13". If not, I'm looking at having to get the 15", any suggestions on which 15" model would be the best for me in terms of what I need it for? Would I be set with a lower end 15"? Any help is much appreciated, thanks.