Revenant Wings.
I don't like how they seemingly lowered the targeted age of players for this game, but other than that, it's probably the best Final Fantasy game to date, gameplay wise. Everything is streamlined and looks great. Enemies can be hard to target with clustered, but your units luckily auto-attack.
Rings of Fate.
Kinda stopped playing it because I want to experience the story in a language I can comprehend, but it's still a fantastic game and yet another testament to how much power there is to draw out of the NDS.
FFTA2.
Didn't play it a lot because it's too text heavy, but seems a lot like FFTA. But I am looking forward to playing it in English.
FFT: The Lion War.
The story, dialogue and FMVs are all mindblowingly fantastic. Yet the difficulty and slow gameplay makes it annoying to play, so I didn't complete it.