I use a PC every day of my life for developing code, website designs, etc. However, I really want a Mac because I think they have a better platform for editing and rendering video.
A year ago, I would have said PC because of 2 reasons: PCs were more of a standard in business, and they were much more flexible when it came to virtualization. However, Leopard and Snow Leopard changed the game. I don't have a Mac, but I want one. When I saw how well VMWare worked on a Mac, I was seriously blown away.
Right now I use Ubuntu 9.10 (Karmic Koala) and use Virtualbox to load XP on my PC. It's about 7 years old and works great. But, if I had the money, I'd switch to Mac for personal (and personal business) use, and run any other business comps on Ubuntu (PCs).