I agree with sparhole.
I have been running Avast Home edition for over 3 years now. It is totally free, doesn't hog resources, updates quickly (even on dial up) every time you connect to internet. It can be used for 14 months before you have to re-register it. You can even use the same rego key on 2 home computers.
The only "problem" I have ever had was a possible false detection of a trojan in CPUZ install file. Up[censored] to latest CPUZ fixed issue. And yes it has captured and quarantined some viruses inbound in email.
The standard skin is a bit ordinary looking but there are many other skins available now. It has modules to protect emails with outlook and webmail clients, instant msgr, P2P, as well as web shield.
Check it out at www.avast.com