honestly...
i bought a DS and had the same problem, bought and beat New super mario bros. and tetris as well...then haven't bought a new game with it..don't get me wrong, it has its fair share of awesome games like advance wars days of ruin and zelda but now, i kinda wanna get a psp cause of God of War-COO, some of the Final Fantasies, Valkyrie Profile and Metal Gear Portable ops...but then again, hardly ever play hand-helds anymore
so i think i'll just quit them...