Mac
Hands down
It's THE reason I got my macbookpro. Sure, it can do a lot of other fancy things, but nothing but nothing, is faster and can handle more data. Not even Alienware (for photos). I've had light tables and editing pages and adobe and aperature all running with over 4,000 images that I'm messing with at one time (and over 10,000 that I'm not) and it's just zip, zap, no lag, wait, stall, or "thinking" required. Multiple programs with MASSIVE amounts of data being used, and it's as fast and as flawless as if I had only a single program open with limited data. FAST AND FLAWLESS.
((It's pretty similar in other areas as well. I'm doing a research project for school, and wasn't paying attention and realized I had 79 tabs open in safari. Not a glitch. The PCs in the house, however, start to get grumpy at or before 10 tabs))
I'm a Mac convert because of the photo and film editing that I do. Macs are NOT intuitive to me (i've learned! But I cut my teeth on DOS, and used IBM compatiables for 20 years... it took me a little while.) The speed and reliability makes all the "HOW do I do this???" in the beginning (and randomly even now, 3 years later) so, so, so worth it.
LOL... they're also built to last. I took a tumble with mine and shattered the screen and broke the hinge and the durn thing STILL worked (do know that you can add them to your 'valuable personal property' insurance to cover repairs if you pull a boneheaded move like I did, or if they get stolen). Macs are NOT cheap. But dang.... do they WORK.