What I set up on all the computers in our company:
Malwarebytes Anti-Malware
CCleaner
Opera web browser or Firefox
Symantec Antivirus (the corporate version, not Norton home junk) or Microsoft Security Essentials
Don't look at porn sites or "free" game sites, etc. Using OpenDNS filters and a SonicWall router helps with this.
And for the love of #$@ don't install a bunch of junk you don't need, uninstall all the pre-loaded garbage, and keep your Flash/Java/browser updated.
Obviously none of these solutions are completely foolproof, if a user installs something without reading and un-checking all the free junk that comes with it, or clicks "OK" on a site even after their antivirus has popped up a warning... there's no accounting for user stupidity!
