What a shock, all the Mac snobs come out of the woodwork . . lol
dont flame me, I'm just poking fun at Mac users fierce brand loyalty
Seriously, It really depends on your budget, and whether your other half moans about the computer being ugly. I think you also need a modicum of tech ability for the PC, whereas if you dont know much about OSs and hardware, I think the Mac "babysits" you a bit more
You get a lot more Computer for your money if you buy a PC, but some of the Macs are really aesthetically pleasing. .
I run 64 bit Vista Ultimate on a 3ghz multi core processor with 4gb of fast RAM with LOADS of hard drive space and I love it. Photoshop is a dream to use, and when I am processing HDR images, it renders 3 times faster than my friends Mac, but as I am not 100% sure of his spec it would be unfair to put more weight on this stat.
I would say, go PC, at least a 3ghz quad core, at least 2gb of RAM, and your computer time will be a pleasant experience. . Also you will find that more of your friends will be able to help with problems as they will probably have a PC. You can say what you want about Bill Gates, but he has got it sewn up. .
Oh, and with the money you have saved over the Mac, treat yourself to a couple of sweet lenses. .
As for the guy thats just installed the 64 bit OS, my friend who works for Microsoft told me to re-install standard Vista, as 64 is quite often slightly slower when it is running 32 bit apps in a 64 bit environment. He did explain (API calls blah blah 32 bit memory addressing blah blah) but I dont notice its any slower, and I like to be able to see all of my 4gb of RAM. .