I am a believer in Norton. I recommend Norton Internet Security 2005. It offers add block, awesome virus protection for both incoming and outgoing email, excel files, etc., SPAM filtering, and even has some Parental controls. Others that I spoke to have had minimal if any issues since they have installed one of Symatec's packages. Auto update of virus definitions makes updates easy.
http://www.symantecstore.com/dr/sat1...CACHE_ID=74456
Paste the link to your browser and check it out.
There are other good ones as well.
jupiter_bob