Like Eric, i use virtualbox;

i've got two laptops, my original with 8 gig of ram, which does pretty good with two virtuals running,and slows down beyond that;

i've got an Origin PC laptop with boatloads of horsepower, pure SSD everywhere, and 32 gig of ram; that thing screams, and i haven't really stressed it enough yet. I've been putting together a clustered example on that one. i spent an obscene amount on it, but i wanted the latest and greatest.

i slowed it down a bit by encrypting all my drives, but it's still screaming fast compared to my productions servers with SAN disks ,or anything i had personally.