If you like point and click games with lots of text, you can't do much better than 999: 9 doors, 9 persons, 9 hours. Professor layton is a good series.
Action: Contra 4, custom robo arena(shit in every aspect except for awesome gameplay), GTA: chinatown wars
Action rpg: the three castlevania games on the DS
music: Elite beat agents(the most criminally ignored music game in existance)
Strategy: Advance wars: dual strike and days of ruin, fire emblem: shadow dragon (It's not the best in the series, but still good.
Rpg: Pokemon: Diamond/peral/platinum & black/white, the world ends with you, mario & luigi RPGs,
Racing: Mario kart DS
Platforming: new super mario bros,kirby canvas curse, kirby super star ultra
other: warioware: touched!