Everyone has different opinions, but here is mine:
I used to have a hefty Voodoo PC which I loved for everything I need it to do. But I changed it for a Mac when they switched to Intel and let me tell you: I WILL NOT GO BACK. My workflow is now really FLOWING, everything is there when I need it (no waiting or crashing), no viruses to hassle with, every app I need gives me joy to use it and it's deffinetly quite faster.
Of course it has bad things too, but they are nothing compared to all the trouble I had to deal with while using W. XP. I found it to be so usefull that my entire staff runs on Mac and the only PCs I use are the ones that handle the ripping process for my printers.
Anyways, it all depends on what you plan to use it, but if it were me, GO FOR A MAC.
Cheers!