If you're really liking the Sim games, then there are two coming out soon.
Sim City DS, which seems to bear much similarity to Sim City 3000, though that might be a bit much. And also, there's
Theme Park, which seems to be linked to the Sim Theme Park and Sim Coaster games, which I quite liked.
Also, in the Harvest Moon vein, the DS game was actually one of the less-impressive ones. There's an array of those games on pretty much any handheld or console platform made by Nintendo.