Have you been told that buying a Mac will avoid problems with viruses? That can be a good temporary solution—until a lot of folks start buying Macs.
 
Macs are relatively safe right now because they are such a small part of the market. As their market share goes up, so will the likelihood that virus-writers will start targeting them.
 
I saw an interesting study recently that compared the number of identified security flaws (that required patching) between the Mac operating system and Windows. Over the last few years, the number of security flaws discovered for Mac OS X has been increasing; recently, there have been nearly twice as many security flaws found in Macs as in Windows. In 2008, there were over 250 security flaws discovered in OSX.
 
So ultimately, there is no "safe haven", but right now you can mostly avoid being the target by not being in the mainstream—though there have been several Mac viruses identified in the last year, and some viruses can infect both Windows and Macs, such as the ones that target MS Word macros.