Okay Shack, help an ol' Bean out here...

I am trying to figure out which virus protection software is best to install on a 5-computer network with 3 computers running Vista Business (64-bit) and 2 computers running Windows 7 RTM (64-bit)

I've been reading reviews, and assuming I want to stay away from Norton (unless it has suddenly not become overly intrusive and burdensome in the recent edition), what I have as my contenders right now are:

BitDefender
NOD32
Kaspersky
Panda Antivirus

In that order of likelihood at the moment.

What I want to know is (1) which is best [cost is not really a concern]?, (2) am I missing one that is better?, (3) is one of those total crap that should be avoided?