I run Word, multiple browser windows, email, and expect to run iLife a fair amount. The 20" iMac Intel comes with 512MB of RAM and 128MB of vRAM. Will these be adequate? Will 512MB really kill my performance? As there seems to be a delay to get an iMac with 1 or 2 1GB sims, can I drop in a 3rd party 1GB simm to give myself 1.5 GB in total (1GB+512MB)? Do I really need 2GB? Is the stock vRAM sufficient to load plenty of photos in iPhoto and/or to have plenty of windows open in various apps? As a Wintel user who hasn't owned a Mac since the original Duo laptop, is there anything else I should consider?