NOD32 is a winner for me for anti virus.
Security Essntials if you want a free one.
most probs i have to clean up are to do with malware rather than viruses. to clean up someone's PC you will need:
UVK to kill processes
http://www.carifred.com/uvk/
rootkit checker like tdskiller
http://support.kaspersky.com/faq/?qid=208283363
malwarebytes to delete the malware
http://www.malwarebytes.org/
ccleaner to delete temp files
http://www.piriform.com/ccleaner
and a good online resource for info on that piece of malware
http://www.bleepingcomputer.com/ is great, if you google [
beepingcomputer.com *insert fake program name here* ] there will probably be a guide on how to remove that nasty *&^*