For the casual dabbler...Elite Beat Agents (read our review)
The family-friendly puzzle category is probably the hardest to nail down with the DS audience. The touch screen simplifies action to such a point that anyone on the planet can jump right in and play (all conveniently marked by Nintendo's "Touch Generations" brand label). But once all the brains have been trained and the blocks cleared, it's the danceable tunes of Elite Beat Agents that'll have casual gamers looking over your shoulder in hushed awe.
Played only with the stylus, you tap, slide and swirl to the beat of pop music legends like David Bowie, Madonna and Queen. It sounds silly, but the infectious "one more round" style of rewarding gameplay should keep not only the puzzle crowd entranced for hours, but also the "seen everything" gamer that's looking for the next underground hit to play before everyone else.
Second choice: Tetris DS