Hi all.. Im going to make the big switch, im going from PC to Mac. Ive been a pc user for damn near 20 years. I bought an iphone 2-3 weeks ago and love it and decided to try the mac book pro. I guess my first question is should i buy from a store or a private seller? ive seen them used and "sealed in box" on classifieds here in california. Is there any danger in this? i could save about $500+ going this route. My thinking is, as long as there is a warranty and im able to add apple care to it and/or its sealed i should be fine right? next question, these people selling them sealed in box.. how are they getting them so cheap so that they can resell them and make a profit? and last im going to get a mac book pro ive always overpaid and overdone it with every pc purchase ive ever made getting things i just dont need. What are the noticeable performance differences between the 3 15" notebooks? I know thats a broad question.. Id just like to know what i wont be able to do w/ the 2.53 and what would make me want the 2.8 w/ the extra video card. I HATE computers that lag, i dont play games and i dont do any heavy video editing. thanks for any advice!