I understand it, but we've been through it a million times and nothing new is ever added into the mix, so its pretty pointless arguing about it.
For me personally, I was split between either a new PC or a Mac - however, for the spec of PC that I wanted I'd have to run 64 bit XP, and thus drivers and support for some of the hardware and devices I want my computer to be able to run was limited which kinda put me off. I don't want my computer to be hard work and I don't want to end up not being able to run certain devices that I already own.
Also software wise, two programs I use for work run native on XP, and two run native on OSX. However I only rarely use one of the XP programs, so the PC was kinda outweighed here by software. Thus my choice was a Mac.
I'm going to allow myself to be pissed off by another OS, but at least I'm going to give it a decent run, and finally get away from the (very plentiful) annoyances of Windows.
So what if it's expensive? I'm not spending your money am I? It runs everything I need it to, and plus it looks kinda sexy - there's nothing to really argue imo. Just pick a platform that suits your needs.