Best internet sharing. Win.

I have 2 computers. A small "server" ( duron750+384MB Ram ) and a workstation. I want my server to be on all the time with these services: Router software, firewall? web and mail services ( antispam ), antivirus.

The big question is: Can I have all these serivces running, in light of only a handfull persons will have access to the computer? It is for personal use, not a heavy filesharing, or a 10 000 visitor web-server.

What windows software should I look towards, and how good are the router software/firewall to enable "ping intensive" games? my experiens is that everything that lies between the connenction and the windows tend to lag.

so is it possible for my computer to connect to internet, through my server and play games? What is your experience around this? And what forum suits this questions better that here?