There is so much misinformation and inaccuracies being passed along in this thread I just had to weigh in here. First of all, buying a MAC Pro for any purpose, even gaming, is certainly not a complete waste of money. The main reason? Any piece of crap PC you build, even if it has the latest motherboard and/or video card when you build it, will depreciate in value about 3 to 10 x faster than a Mac Pro. Most PC people are blissfully unaware of this fact. I was unaware of it myself until I started buying macs. You can resell them years after you buy them for large sums of money. By comparison, any PC I have ever bought ended up just being a paperweight.
My point? Well do the math, is it better to buy a $2500 Mac Pro and use it for 3 years and then still resell it for $1500+ dollars, the whole time using an incredibly well made computer or pay $1700 for a PC that in 3 years you could maybe get @$300 bucks for?
Next, the poster I quoted above says that using a Mac Pro with Boot camp is a PITA... can someone please elaborate on this? I have never had an easier time in my life than I have with my 2010 Mac Pro with Boot Camp and Win 7. It just loaded up and worked out of the gate. I have the 5870 video card, I can download all the latest ATI drivers in windows, and all games I have tried to play are flawless. What is the PITA part?
Would I buy a Mac Pro just for gaming? Probably not, but I wouldn't buy any computer just for gaming. How could you not get more out of a computer than just gaming? Don't you go to school or work or something and need to use office apps? Don't you Take photographs? Listen to music? Take videos and want to edit them? All of these things are tasks just about any human being can do on a computer. Do them and game on a Mac Pro, then three years later sell it for 70% of what you paid for it and buy whatever else is the thing to have at that time. Also, the entire time you own it you will have the benefit of 2 operating systems, not just be married to one. Its literally 2 computers in one from that perspective. Its the best value in computing. The Apple brand and build quality are WHITE HOT, there is nothing better made in personal computing right now than their hardware. The Mac Pro is the made finest personal computer I have ever owned. I say go for it.