I wouldn't recommend using VirtualPC until they finally decide how Windows apps are going to be run on the Intel Macs. It might be through a newer Univeral Binary of VirtualPC that will support the Intel Macs, or it might be through a transparent layer similar to WINE.
Regardless, at the moment I wouldn't use VirtualPC for gaming. There are enough top-billing games out there with Mac and even Linux ports. For other games, keep the PC until the solutions for the Intel Macs become readily available. Just because you get a Mac doesn't mean you have to get rid of the PC, especially if you do gaming and web design. The PC will help you get an idea of how the page looks on a PC running the current stock of browsers while the Mac will give you its perspective with its current stock of browsers.
