The debate about the best virus scanner

Yesterday I kicked off a discussion within the it company I work in about virus scanners and which one is best. 3 people including a php programmer, sales rep / desktop support specialist and myself a webmaster were quickly arguing with all 3 of us looking after our machines and networks with completely different solutions. The results were the php developer using kaspersky, the sales / desktop support specialist swearing by avast and myself using commodo.
I will investigate all three programs suggested give some comparisons between each product. I will also be re- enabling comments on the blog shortly and would love to no your thoughts and virus scanners you are using.