I use virtualization software and sandboxie, so I dont have adware/virus problems with my PC
Now that vista has come out they intentionally broke the ability to use this technology.
I never understood the no virus claims of mac, its a computer. If someone writes a virus for it it will get one. Virus vendors are like any software vendor (yes, its a business). There are more titles available for the system that has most of the market. I mean If I want to setup a bot net to sell for $50,000 to an ad firm or more shady group then Im going to use PC because most people use it and the odds of exploting a large number of machines is better.
However, with phone becoming java enabled I'm waiting for a cell phone MMS virus to break out

Lots of money to be made there! Everyone has a phone weather they use mac or pc, hehe.