I've been having pretty much endless problems with my current wireless networking setup (thomson 530 modem with cisco WRT120N router) so I'm gonna try fixing it one more time if it doesnt work I'm gonna replace the whole system with a modem with the wireless built in...
The modem needs to have built in wireless G, and have decent range, no disconnection problems when playing games online, be 200 NZD or less, and the ability to easily set it up and configure would be preferable.
You cant guarantee the wireless wont disconnect, especially if there are lots of wireless networks on the same channel in your area. The most congested radio frequency is likely to be channel 11, so maybe change to something like channel 6 or 7 when you setup the wireless. Or use Ethernet for gaming if you have any wireless problems.
Qualified in business, certified in fibre, stuck in copper, have to keep going ^_^