My present setup is a 4-port d-link adsl router with built-in modem connected to a 512k nildram connection. I have 2 pc's connected to it,one with win2k and one with winxp.The reason for 2 different os's is just for the user experience.

I'm wanting to make a more secure setup by having another pc run as a bastion host server.I will be upgrading my connection to 1meg shortly so the server will also be running a counter-strike games server, just for local friends.So am i right in thinking that i need a router with built-in modem where my connection comes in.The server will attach to that.Then i need a switch connecting from the router for my 2 pc's to connect to.I also want the 2 pc's to be able to communicate at 1000mbps,so i think i'll need 2, 10/100/1000 NICs and the switch will also need to be capable of 1000mbps,whereas the router will be ok at 10/100mbps.Or does the server need 2 NICs, one for the router and one for the switch?

If I Have understand Correctly, Yes, you want to use the two computers exit to Internet trough the third Ones using some kind of software, isn't it?
Well in that case, you donĀ“t ned the router, the third computer will done the routing job, and the server will need two NICs, one for the Wan conected to the ADSL, and the other to the Lan.