Kaspersky is great whether you get the AV or the full package, I have used both before and really i found I have fewer problems using spybot s&d adaware pro and a good firewall software the only thing i liked better about kaspersky Internet suite is that the spyware protection is realtime so that it will keep alot of different spyware from infecting your system where as spybot and adaware are post-infection removal tools (although spybot does have an immunize feature in my experience it doesn't work very well, i've seen many systems infected with spyware that is in the immunize list). KIS firewall is fairly top notch as well, really verging on linux like paranoia which there is nothing wrong with that either. personally on my main machine that goes out via various protocols to connect to work etc. i use KIS and still use spybot, adaware and about a dozen other tools to keep the machines secure but on most of my machines just kaspersky and spybot, etc.
It really comes down to how much security do you want/need for what you are doing with your system personally i perfer the free software and take the time to edit the services and such that system is using to ensure security that way and I also have made sure to have a firewall at the router level and at the system level.
Hope this helps
Brett snipped-for-privacy@gmail.com