I have a small office (me and two employees) with 4 computer workstations. I am utilizing the Windows Home Server. It's simple and small and most importantly, backs up every computer on the network nightly. It has some irritating quirks like requiring every computer's name to be a user name.
I decided not to put AC on the Server though. I'm using my main office computer as the main computer. I had your fears of loading AC onto the Windows server and regretting it. In hindsight, it would work fine.
Granted, I'm just cranking up with AC so I'll keep you updated how it goes.
Just a caveat on AC. It's simplicity is it's greatest benefit (and price). I showed my new front office employee the main aspects of AC in about 10 minutes including importing items, scheduling, rolodex, templates, etc. She was a little anxious about learning a new piece of software and the lack of paper I desire, but after that she was actually excited. She said "cool" about 5 times while I was showing it to her.
