That is because most of it is opinion...and like a mouth, everyone's got one...(that's not how the quote goes, but the profanity censor won't let the crude reference to the hinder end of the ailimentary canal through! ;) )
What is true, however, is that in the (Computer) Security Game...if it's free, it's (generally) useless. The flagship of this is AVGFree, which is about as effective as a screendoor under the waterline. Which is ironic, since the paid-for version is a decent program.
In any case, you generally get what you pay for, and an $80 suite is almost assured to be better than a $20 suite.
To add to James' list...
ca Internet Security 2009
Norton 360 3.0
There are other suites I am aware of (Panda and VIPRE[?]) that I have no direct knowledge of, but are supposed to be quite good as well.
EDIT: Oh, if you're going to buy on-line and do a digital download of the suite, ensure your go to the publisher's website (Symantec for Norton, etc). Do *not* download from third party sites, as they are either cracked (and have added "features" you don't want), or outright malware.