What is your favourite DS game and why.

TWEWY kept me playing for ages after the main storyline to collect all the secrets. That and Disgaea are two of the greatest games I have ever played for the DS (Despite the grinding, I'll kill you Baal!!)
Honourable mentions goes to Trauma Centre and Shin Megami Tensei, though I'm waiting for Strange Journey to come out in English.

I love the castlevania and kh 358/2 days and all the good ones, but i really like pokemon mystery dungeon blue rescue team and the megaman zx series.