The conversation seems to have moved past this, but here are my DS recommendations in no particular order. Some are probably very hard to find now.
DS: Shin Megami Tensei: Strange Journey, The World Ends With You, Final Fantasy III, 9 hours 9 Persons 9 Doors, Radiant Historia (the best game on the list IMO)
3DS: SMT IV, SMT: Devil Summoner: Soul Hackers, Zero Escape: Virtue's Last Reward (the sequel to 999 above).