My roomate and I just finished playing both of the Lego Star Wars games (pretty awesome games I thought) and I have an adapter for my Xbox controllers so we can play multiplayer games on my PC (like FIFA and Lego Star Wars).

Anyone have any suggestions for other games we could get to play offline multiplayer with game pads (minus emulators, since I already have a few games emulated)

I don't know about with game pads, but I will suggest the Worms series as awesome offline multiplayer games.

Gish. Its mostly single player, but the mp can be pretty fun.

joytokey lets you assign gamepad presses to keyboard and mouse functions. Allows you to use the gamepad on any kinda game.
You can even have the joystick operate the mouse. But of course, it's not as good as the actual mouse.

As for games.. I suggest looking up multiplayer games at gamehippo.com. My old room-mate and I had a blast playing all sorts of stuff from there.

Off...line? *gasp*

hah, well I wouldn't mind being able to both play online (for example crimson skies on xbox two people can play splitscreen online)

thanks for the suggestions so far guys