Hmm... no AD setup? Well I will give you my experiences but they are AD based - which can be pretty important for management and deployment. I have worked with Blink, Kaspersky and Trend Micro and only liked TM of the three.
When I moved away from Kaspersky I seriously looked at ESET. Seemed like a great product with a small, fast footprint. One of the things I really liked was the ability to push software packages other than ESET through their admin console. I tested it through AD groups but IIRC you can create your own groups within it for non-domain setups. You might find that very helpful since it sounds like you have no group policy options.
Sadly ESET was more expensive than TM so we went with TM - not that there is anything wrong with the AV part of TM just ESET had some nicer features and ran a bit faster on some of the ancient machines we have laying around.
As for TM its pretty easy to manage - although I don't think it allows for custom groupings outside of AD (but I'm not sure). One of the benefits for you if you have to touch every machine is that it installs very quickly. I find it installs in an average of 2min (assuming 'scan before install' is not checked) although there will be some network usage to update once its installed.
I did find the webpage install a bit of a pain as it required a bunch of activeX exemptions be added for our setup. You may not run into the issue though and, if thats the case, you can just send people a email with a link for them to click on and install the software on their own
Another plus for TM is that the licensing is incredibly easy. Aside from VMs they make no distinction between pc, server or TM server. You could install a TM management server on every single computer you have a TM license for if you wanted. I don't know if you are planning on expanding to or have remote sites but this can be very useful in terms of setting up remote update servers
Nate_007, one question I forgot to ask. Are all these viruses coming from within the workplace, or from people who take laptops home and do "who knows what" with them?
I would love to enable the feature that requires routing of company laptops taken home through our firewall but I have neither the bandwidth nor the buy in