Im considering a new 12" PB w/ or w/o SD. I currently own a 12" Rev B with 768 MB ram, which is a fine machine, but is a little slow at times. I usually run iChat and Safari, with occasional word use, possible dvd burning and occasional WoW,Warcraft 3 etc. My PB is my only computer so it is used every day, which is why im considergin an upgrade. To buy a new PB I would sell this one and use that money plus some I have saved to pay for the new PB. Is it worth it to upgrade? I mean I could really use the speed and possibly the SD drive, but I could also save about $400 or so dollars by not upgrading.