Well it depends on what the client needs mate.
If you only have like < 10 machines then i woudl probably just buy 10 copies of Eset or what ever you like as i cant see the need for a mangement server for this.
You shoudl also always have a commercial AV solution instead of relying on MS Security essentials mate.
Im a strong believe of having AV on servers as well.
You can go with cloud solutions like Webroot but the problem with that is, there is no signature stored locally and you have to be connected to the net for it to do anything.
We have Webroot but i will be gettign Eset next time round i think because the scans on webroot are pathetic at best and so many false positives i lost count.
What ever you do just downt go down the Symantec/Norton road mate, you will kick your self if you do.