1) netgear really sucks, their routers are a joke and the majority of the time simply loose the settings you program into them - or they never program them in the first place. replace that POS
2) a 10 second google, microsoft, or xbox live search all reveal to you that you need to setup your xbox ith a static IP, then forward all ports associated with xbox live
My Netgear routers running DD-WRT firmware work just as well as Linksys running the same firmware. IMHO Belkin is the #1 worst router and D-Link #2 worst router.
With that said you need to bridge the modem, set the router for PPPoE and then enable UPnP in the router. No need for the mess that is setting a static IP address and manually forwarding ports. If the xbox needs a port forwarded let it handle itself. -- PRescott7-2097