I am looking at the 15" 2.66 Ghz i7 MacBook Pro 500 GB Serial ATA drive @7200rpm Hi-Res Antiglare. I am wondering if I should upgrade to 8 GB. Is it worth it for $400 extra? I know you're going to ask what I do with my mac. Well, photos, mostly. But a laptop is ALL I own. Should I go all out and get everything high end or wait on the RAM? That's my only other decision left before ordering it.