If you plan on playing ona big screen then you'd do well to either get a NTSC Gamecube, or a PAL Gamecube + a Freeloader disk, then get all NTSC games. Make sure the console has a digital A/V out socket as you need that to be able to use a component cable(with this cable and most NTSC games you can run them in proggresive scan which gives a superb picture, even on a massive screen). I use my Gamecube with my Sanyo Z1 projector and the games look amazing
As for games, the ones you mention would be a good start, my girlfriend is also a non-games player(apart from a bit of DS). The only console games I can tempt her into playing are Super Monkey Ball 2(favurite due to variety of the mini-games), Mario Tennis, Mario Strikers(footy), she also used to like Mario Golf although we now prefer Hot Shots Fore on the PS2(the putting works better).
There are loads more fantastic games for you to get for single player fun(Resi4, Pikmin2 etc.) but those are my recommendations for you & your girlfriend.
Great thing is you can probably pick up all those including the console for less than the cost of a 360 Core