I switched from PC to a Mac recently. If you've got an Intel based Mac, you can run Windows on it. Many people are not aware of this.
I have a Mac Pro and am able to run Windows on it via the Bootcamp feature of Mac. I've got Windows XP Professional on it and it works great. Also, I've got VMWare Fusion virtualization software on it that lets you run Windows side by side with OSX without having to reboot through Bootcamp. I have several Windows only programs that I couldn't do without, but it's not an issue with a Mac now.
If you have the money to pay the price of a MAC it's a slick setup. I run Mac OSX for web browsing, email, video editing, photos, music etc. I run FSX via Bootcamp (this allows all resources to dedicate to Windows) and Office, other Windows programs through VMWare Fusion side by side with OSX.
Running Windows on a Mac: Boot Camp, Parallels Desktop & VMware Fusion - Notebook Forums and Laptop Discussion
VMware Fusion: Run Windows on Mac, for Mac Desktop Virtualization