as FDDI goes at around 100mb this would probably be the best option.
It depends on the budget and purpose though. If the machines are all going to be pulling down data at the same time you want as much bandwidth as you can get (which will be costly), so that each machine gets a fair cut, if they will all be connected, but only performing the odd mail check and opening a few sites, then smaller bandwidth will be ok as they can just take all the bandwidth, then stop, and leave it to the other machines.
In this case, I would say FDDI. The reason is because you said single connection. FDDI can operate up to 100Mb over fiber and would be your fastest choice. SONET is a multiplexer which combines several connections into a single fiber connection.
Ep, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS