Ok, that's cool.
I'm not a gamer so rather than recommend a specific motherboard, I'm going to make some general recommendations instead.
I don't know if you've already decided on which cpu you want - most people tend to have a preference for either Intel or AMD. Personally, I like AMD and would recommend a retail boxed dual core Athlon, AM2 socket. Don't go for Semprons or Celerons (if you are inclined to opt for Intel).
As for motherboards, I would go with one of the following brands:
Asrock, MSI, Abit, DFI, Asus (normally ok), Gigabyte (possibly)
Stay clear of PC Chips, Jetway, Foxconn, ECS
Nvidia chipsets are pretty good, as are AMD/ATI ones as far as I know. Probably best stick with Nvidia though as you're using an Nvidia based graphics card.
Make sure the board has plenty of potential for upgrading (eg 4 ram slots ideally, support for newer/future cpu's, etc).
Stick with decent brand memory, such as Corsair, Crucial, Kingston, OCZ etc
If anyone else who's into gaming has any more specific recommendations to make, then please do so.....