id say, out of those 3, nortin or defender pro (i have no experience with it though) would be the best. mcaffee is by far the WORST virus protection my parents and i have EVER seen. on my parents old pc, it let in 6 backdoor trojans, not to mention a slew of other viruses and such, without doing a thing. id say norton is pretty good, but ever since the 2nd to last time i had problems with my pc and came here for help, ive moved to avg free, and it very good.
edit: o and btw, the backdoors were all a variant of trojan.backdoor.death . any idea what they do? lol, besides make your pc not work.