I use PING (Partimage Is Not Ghost) an open source imaging program. It
boots from a CD into an ISO Linux kernel, it's menu driven from there.
I use it to log into either an SMS or CIFS server where the images are
stored. It has a branch where you can go from device (USB Drive?) to
device but I've never used that. It won't overwrite a locked partition
so if I can't get the machine to shut down elegantly before imaging I
use a Knoppix live CD do delete all the existing partitions before
imaging. This is the imaging engine in a FOG server.
It works! It will even image Macs!
Download the ISO image, burn a CD and give it a try.
For anti-virus I use AVG. I have the free version on the PCs but pay
for the network version (they offer a 50% discount to education). When
I get my virtual server set up I plan to roll out the network version.
It has been effective against the latest round of viruses, better than
symantec which is what we were using before.
Don't forget to spend some time creating a default profile before you
make your image. Very important in Microsoft land....