Network Setup Small Office

We have a law firm client.

They'd like us to setup their small office, they're Mac based, about 4 iMacs, 2 Macbooks, 2 internet ready TVs.
They also have about 2 printers to share on the server as well.

Wanted to know if a Mini Mac with Snow Leopard Server would be good enough or a tower?. Would also like to connect a hard drive to server, so the TV can access movie files too.

What would be the best setup for a small office like this? also what is a good backup solution for macs? The server is where most of their files will be getting stored.

Any recommendations?

Thanks

I set up an office similar to this. Used an Airport extreme for the main router, airport expresses connected to the printers. MacMinis with Snow Leopard server for file and print services. Backups were done with time machine to external drives attached to the Mini.