two different anti viruses

Running different AV software on each side will not cause any conflict. However, AV software for the Mac side is generally unnecessary. It can cause your Mac to slow down and may prevent the system, or other programs, from running properly.

There are no viruses for the Mac in the wild. There is malware, and there are vulnerabilities in Java, Flash, and PDF protocols, among others, but Macs have built-in anti-malware checks, and provided you take basic internet precautions (don't install software you don't know or trust; don't put your personal information or passwords on websites you don't trust), you should be fine.

Matt

Regarding Mac malware, and how to protect yourself from it, you'll find more information in my Mac Malware Guide.

Note that there's no increased need for Mac anti-virus software just because you have Windows on another partition. Your Mac is in no danger from Windows malware. However, if you choose to use anti-virus software on the Mac, that will not cause a conflict with the anti-virus software on the Windows system. Thos are not running concurrently, and neither one should be scanning the other system's partition, so they will not conflict.

another user in another post mentioned that theoretically AVG on the windows side scans the mac end as well......

In theory, if the Mac partition was accessible to the Windows system, it could be scanned by the Windows anti-virus software while Windows was running. There would probably be no point to that, because very few Windows anti-virus tools include decent signatures for Mac malware, if any at all. Further, it would be exceptionally dangerous to allow a Windows anti-virus tool to make changes to a Mac system, since it wouldn't know what it was doing in that regard.