I started using ZoneAlarm free version. Very good firewall. I was using PC-Cillin as my virus protection. My mistake has been getting sucked in to using the "paid" versions. Every year I can get both "paid" versions free with rebates. Unfortunately each is trying to take over everything. PC-Cillin 2008 would not even install with ZoneAlarm present. It would not continue installation until I took off Ad-Aware and SpyBot. After I resolve the current problem with PC-Cillin I'll probably get rid of it and go back to an earlier free version of ZoneAlarm and something like AVG antivirus. I have several other computers with the ZA/AVG programs and haven't had any problems.
I am quite happy with both AVG and Zone Alarm- I support them both, though I submit these thoughts for your perusal:
I recommend the addition of AVG Anti-Spyware to your software stable. AVG Anti-virus is quite good, but I have found it to be compromised on several occasions. AVGAS compliments AVG Anti-virus, and the two together are quite sufficient.
AVGAS is fully functional when installed (includes realtime scanner), but will fall back to manual-scan-only if not purchased. This manual scan is quite sufficient, if updated and used for scanning every couple weeks or so, and is invaluable to have onboard in cases where the main AV scanner has been compromised.
AVGAS is compatible, and will run alongside of any Anti-virus product. It is the old Ewido trojan hunter.
WRT firewall, I like ZA, but my preference for the last couple years has been toward Comodo Firewall. When configured as "firewall only", it is lighter than ZA, and without the "Buy me" nag boards, yet it's method of interface is very similar to ZA, making it simple for joe-user to operate.