I am doing exactly what you're talking about here, although I'm still on Server 10.5.
In my family there are four Mac users and three Macs (2 imacs, one laptop) plus a server. The server is an old G5 tower but I am going to update it to a mini with an Intel chip soon so I can put us on 10.6. The server has a second Ethernet card to face the Internet. It handles DNS, AFP, Open Directory, DHCP/NAT/firewall, mail, iCal, and print services for us.
There are two kinds of mobile directories. One is the network directory, which means all your data resides on the server, and you can roam from client to client to access it. When you log in with your network account to a client computer bound to the server, you run your programs locally, but actually have to pass all of your data back and forth over the network. This works fine for email, surfing the net, and other light uses with your Ethernet-wired home computers.
The other kind of mobile directory is the portable home directory. This is what we have on the laptop computer. It actually synchronizes the data so you have one copy on the server and another on the client. Then you can travel with the laptop, modify your files, and a copy will be put back on your server the next time you come home and connect to your network. Problems arise if you simultaneously modify a file on the server and also on the mobile directory- you'll have to choose one or the other version (or a copy of both) the next time you synchronize. It provides a crude backup of your files but is no substitute for a Time Machine or Super Duper backup.
I also set up a portable home directory on my daughter's main computer for her account only, because she is a heavy multimedia user. Running programs like iPhoto and iMovie is very very slow if you have to move the data over your network, even with a gigabit Ethernet setup.
I would suggest a couple more things:
- When you set up or upgrade your server, the very first thing you MUST do is get your DNS working correctly both forwards and backwards. Do not attempt to set up any other service before you are absolutely sure this is working well. You don't need to have your individual machines visible on the Internet or even have a publicly visible DNS presence pointing to your server, but you definitely do want a static IP number in the local 192.168.x.x subnet for each of your devices on the LAN side of the firewall. We name our machines after Tolkien characters: aragorn.mayfamily.local, gandalf.mayfamily.local, etc.
- If you use portable home directories, don't attempt to synchronize anything in the Library folder. For your email, use IMAP accounts, that's what they are designed for. Synchronize your calendars, address books, etc., with .Mac.
Good luck!
