As a computer science major I feel like I should contribute something to this thread... but I'm not sure there's much left. I'd probably just end up repeating things others have already said.
I use Macs because I can afford them, and with VMs I can run every other operating system I want. Currently I'm using Parallels Desktop 6, and I usually can't tell the difference between running Windows or Linux in the VM vs. rebooting the computer into the specific OS. As a computer scientist/programmer, I love Mac OS X because it's a POSIX OS (basically a version of Unix) and I can install almost anything that is built for Unix. I concentrate on web design, and it's great having Apache w/PHP, MySQL, memcached, etc. all ready to go, with the flexibility to install more as I need it.
I generally recommend Macs to those that can afford them because they can get the best of all worlds. I have nothing against PCs, I've owned and built several. I just prefer the flexibility, reliability, and ease of use.
Originally Posted by Jan Paalman
While normal users really wouldn't use such a large(at this point) amount of RAM, there are a lot of reasons to have such a machine. High end database servers is one example, and it's nice knowing the consumer version of OS X actually could be used in this way. I dislike Microsoft's marketing tactic of having so many "flavors" of Windows. It seems to make it confusing for those that don't know much about computers, and force others to pay more for what they need.