Comodo Firewall is the best according to studies. The best antivirus is a highly disputed subject. I use NOD32 because it doesn't slow down my computer and has great protection, but you have to pay for it. For a free antivirus, you should probably use
AVG Free. It's pretty good and doesn't put a large load on your computer. If you need any more information on antiviruses, take a look at
AV-Comparatives. They have done extensive research and tests on many antivirus programs.
SirRubberAhoy, AVG Free is a very good antivirus. It is almost as good as the paid version, and now contains an antispyware feature.