cAPSLOCK on 31 August 2008
Dead Rising would be your best bet, it's open ended and fun enough you can keep going back to it, plus you get to keep your character instead of starting a new one over and over again.
As for the others games mentioned, if you have a PC, get them on that instead of 360. Main reason being that player made mods will keep you coming back long after the initial game wears out its welcome.
There's some interesting stuff in the works for both, and to give you an idea: Counter Strike and Team Fortress started as mods.
3rd Party Wall of Shame
http://www.nintendoworldreport.com/forums/index.php?topic=30478.msg581036#msg581036
