Are two virus application necessary?

Currently my Mac is protected via McAfee. Is it recommended (or needed) that a separate security program be installed on the Win7 environment? Any suggestions or guidelines are appreciated.

 

Yes it is, in fact it is more important on the Windows side than it is on the Mac side. And the Mac side AV doesn't scan what goes between the Virtual Machine running Windows and the internet.

I suggest Avast or Microsoft Security Essentials for Windows, they are both free. I also suggest avast for Mac, which is also free for non-commercial use.