How well can I expect a 12" Powerbook 867/640/Tiger to do with Word/Safari/iTunes/Adium at the same time? Just basic computing? Perhaps the occasional movie? $400 CAD w/o disks. $430 with. Battery holds about 3 hours (probably under), apparently in perfect condition. Good deal or should I shell out an extra $200-250 or so for a 1.5 Ghz?