All I'll say is I use ESET Smart Security.
Asking for "opinions" on AV security and firewalls is like opening Pandora's Box.
1. Everybody has their favorite.
2. Theirs is "better" than the other ones.
3. This one was once good, now it's crap and I use this one now.
4. This one or that one uses too many resources.
5. The whole thread devolves into a pi**ing match and the person who asked the original question is now thoroughly confused.
Google or Ixquick a search on AV reviews, etc. Make your decision and purchase it.
I have seen too many threads go on ad infinitum, ad nauseum about AV and firewall opinions.