bump.. try Firefox
http://www.mozilla.com/en-US/
Yeah there's very few viruses for mac, but that's not to say you can't stay completely virus free on a PC if you have enough sense. Try NOD32 Smart Security if you're having issues.
As far as why this here's a quick explanation I copied.. much easier than typing it myself
The mac *can* get viruses, but in practice it doesn't. The reason for this is two-fold. The first reason is that Macintosh computers are hardly targeted for viruses compared to PCs. After all, what's the use in writing a virus on the mac, since it will only affect 5-10% of the computer world. The second (and more reassuring) reason Mac's are more virus secure is because of the UNIX underpinnings that make up OSX.
In windows, the normal user account is set up as an administrator in most cases. This is good for the user in that they have free reign of their computer to do what they want without being prompted for a password. The downside is viruses that get into their systems also have the same free reign to install themselves and start trouble without the system questioning them. On a mac however, even when you are logged in on an administrator account, the computer is allowed far fewer privileges, meaning any software that tries to install itself or modify your system must first receive your password. Meaning, nothing gets installed or modified unless you allow it. You can experience this simply by downloading a widget in safari. Before the widget installs itself, your computer prompts you that you've downloaded a piece of software that is trying to install itself, and asks your permission to proceed.