I use avast free on my trading computer and avg on my old personal computer. avast caught a trojan that avg didn't, hmm? Not saying avg is bad at at all.
Recently I having been shutting down zone alarm free because I did a speed test and it kills my speed by 50% from my ISP, no kidding. I get 3 meg down with zone alarm and 7-8 meg down without. I run a lynksys blue box and it passed all leak test. Heck there 50 bucks and can do NAT.
There's one other program you folks might want to check out. It's called Process Guard, search google, and it alerts you any time a program has been changed from it's original. Does some other stuff too.