Which anti-virus product is better?

Hey Guys, this is my first time to write in this forum, but I have always found very helpfull solutions here. My company has been having trouble with spyware problems and want to protect the server. I am using 2000 server and Exchange 2000. I am looking for the best anti-virus, anti-spyware and firewall product in the market. Some people have suggested either Kaspersky or NODE32. Please help me choose the best one.