What is this "crappy" memory management of OS X that you speak of? When it comes to memory management, OS X is definitely among the best from my 14 years of experience with modern operating systems. For what it's worth, I regularly run two VMs in VirtualBox totalling just over 2gb of guest RAM allowance, on a 4gb machine running 10.6.8, and I don't suffer problems with this. Users of 10.7 claim that it's a wee bit hungrier than 10.6, though I still can't recall the last time I saw anything else than "Swap used: 0 byte" in the Activity Monitor.