My network has this computer hard wired and DMZ'ed, a wireless 54g laptop (not switched on when my problem occurs) and a xbox 360 with wireless WGA600N adapter in N only mode plus i've tried the old 54G adapter with the xbox and i still get the same issue. Obviously when i'm gaming on the computer the Xbox 360 is off but the adapter is still on.
I never had this issue before using a wrt54gs. I've updated the graphics drivers and re-installed audio drivers and tried countless other things like turning off windows firewall and software firewire, disabled QOS on router, disabled SPI on router. I put this computer in the DMZ and made sure the IP was not left in port forwarding or virtual server settings. Only thing i havn't tried yet is "application rules" but the way i see it, if the port was not open then i wouldn't be able to start voice chat in Yahoo.
My network is setup as follows:
192.168.0.136 GamingPC
192.168.0.150 Laptop
192.168.0.220 Xbox360
192.168.0.250 WGA600N adaptor
192.198.0.198 MN-740 (old xbox adaptor)
All are static IPs and have a reservation in the DHCP. DHCP IP adrees range is 192.168.0.2 - 192.168.0.251
I'm not sure what other info you may need but just so you know everything else works fine, this computer sees all devices on the network and all devices see this computer, streaming to the xbox works fine with WMP11, WMC and TVersity. Bit torrent works fine and my download/upload over the internet is right where it should be (7000/354)