There is, of course, a third free anti virus -
Active Virus Shield.
I've known about this for a while, but they've only just released a Vista compatible version. The footprint is OK (It runs on my virtual machine OK with only 512 MB RAM in Vista) and it's based on Kaspersky so the reliability is fine.
Oh, and you might as well see a few screenshots too.
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PC: X2 4200+, 2GB RAM, X1650, 940GB HDDs, Audigy2ZS Platinum, HVR1100, Vista Home Premium Laptop: Advent 7203 (T5300, 2GB RAM, 80GB HDD, VHP) Server: WHS (XP 2800+, 1GB RAM, 820GB HDD)
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