Ken...cant really recommend any particular one..there are loads of free ones out there, such as spybot etc, that are very good..As for Nod32, comparing it against the rest, which you can do here:
http://www.eset.com/products/compare-NOD32-vs-competition.php then, the rest don't compare. I believe that NASA and the FBI use it, so thats good enough for me.....If you would like a copy...(a trial version that last for 40,000 yrs :-) then email me. It updates a few times a day....regards...scott