At home I use:
IE 6.0.
avast! antivirus (free edition)
AdAwareSE and HijackThis!
All-In-One Secretmaker: this software is good. It has handy functions like auto clearing of cookies/cache, a Bayseain logic based spam filter etc. For more info seethis.
In additon I also have:

ZoneAlarm Firewall (freeware)
Google Toolbar (easy search + pop-up prevention).
Simple File Shredder (Kill important files)