Windows Home Server anti-virus recommendations

Have just got myself a new Windows Home Server (a Tranquil PC model) and loving lots of the features, but I can't help feeling that with all of my valuable data concentrated in one place, it's slightly vulnerable.

So I'm looking for recommendations for WHS compatible anti-virus software.

WHS is unique in a few ways, so just picking an AV package off the shelf may not work (and could be disastrous). It's a Windows Server OS, but for home users, so a lot of personal AV software won't install - but I don't want to be paying Enterprise prices for home AV! It does some unusual tricks with the file system, whilst it is NTFS it does clever stuff with it's storage pool to present any number of physical disks as one storage pool, and does data duplication of shared folders across the physical disks. Because of this naive AV/disk tools could do more harm than good.

I am very, very rarely going to be on the console, so I don't want most of the "extra tools" bundled with AV products (mail scanning, web-malware detection, and so on) just file and memory anti-virus protection without bogging the machine down. I don't mind paying, but nothing extortionate.

Thanks everyone, having looked into it further (and followed Gcoupe's link to the WGS security forum) it looks like the front runner for anti-virus on Windows Home Server is currently the following:

• Avast! 4 Windows Home Server edition (or the Avast! 4 Professional Family Pack to also get licenses to run Pro edition on up to 10 desktops/laptops for only double the price of the ghome server edition alone)

Other AVs not explicitly for WHS but reported to work properly.

• AVG Anti-Virus Business Edition 9 (their FAQ recommends this edition, but it is priced more like a business version than a home version)
• ESET NOD32 Antivirus 4 Home Edition (they have a knowledgebase article on installing for WHS here)

Important things to note, only buy/install the anti-virus/malware scanner versions of the software, be very careful if you're going to get versions with firewalls and other network scanning, the first thing they'll do is kill all your remote access to the server - this is a big problem on a headless server.

I've decided to go with Avast!

Update: As this question's still fairly popular, I'll add that the free, open-source anti-virus Clam AV has just been ported to WHS (review). Get it from the WHSClamAV project page on Sourceforge. Note that this is just a beta release and isn't finished yet. As such it has some fairly major limitations, it doesn't do on-access scanning yet, only on-demand, it doesn't auto-update you need to manually start it's update, and it doesn't clean viruses by default, just notifies. However it has a lot of promise for the future.

F-Secure Home Server Security 2009 was an option but has now been discontinued by F-Secure - as of March 15 2011 it is considered an end of life product