Antivirus software for UNIX

I know that it's not necessary to get antivirus software for UNIX operating systems, but could someone please recommend some anyway? Does McAfee make any?

Symantec seems to have a product:

You've gotta be careful of the terminology. Very strictly speaking a virus is a piece of machine language code that is added into the free space at the end of the last page of an executable. It must be very tiny since free space is tight. Unix users rarely if ever download executables and there are many different machine languages, each with multiple executable formats. This makes unix based viruses very unprofitable.

But put some machine language in a gif file and you have a different situation. Unix users will download a gif file. Strictly speaking this is a trojan horse. But loosely, some folks will call this a virus. Or they talk about a gif file having a "viral content".

So a virus scanner on unix can make some sense provided that it doesn't take a real strict view of what constitutes a virus.