As a service to your brethren, could you let us know the hit rates from Clam on your Mac?
1. In files only available to your Mac
2. In files shared between Mac and Windows (VM/Boot camp etc.)
3. Viruses that can affect your Mac
4. Viruses that you are just a carrier for.
On all four counts, the number is 0.
All I've got up until now is false positives from the days of yore, when I used MS-DOS, and was interested in viruses and anti-viruses
Remember things like Flu-Shot plus, the pakistani virus and it's remover programs, or the ping-pong virus and it's removal programs? All safely tucked away in a folder named dviej (oldhdd in English) from the time of my DTK-286 with amber monitor and Ati Wonder (not EGAwonder, not VGAwonder, just plain wonder) card, MS-DOS 6.22 and Windows 3.0.
I set exceptions for that folder on all my windows machines (from my DEC Starion 700i, then my Thinkpad i series, then my Toshiba), but in the MAC, I got lazy about it, so, as ClamAV's signature files refine, I finds more and more of this legacy code, and let ClamXav erase the files, since I realize I have no use for them anymore.
The last time I was hit by a virus, was in 1996, it ate my hard drive, and my thesis with it, lucky me, I had backups on my paralel port Travan Tape Drive, so, all that was lost was a day of work (to restore) + 1 day of updates on the thesis docs...
And that's the other lesson, have good backups!
I know my Mac is less susceptible to virus/trojans/worms, I also use safe practices when browsing/downloading files, but nonetheless, I do not kid myself thinking that this alone is enough, so, on top of that, I run an Antivirus, have the SW firewall enabled, and run a firewall on my AP.