I would say, only buy a DS Lite if you are interested in GBA games or want to save $40.
Some recommendations:
Action Adventure:
Castlevania: Dawn of Sorrow (or one of two other Castlevanias)
GTA: Chinatown Wars
The Legend of Zelda: Phantom Hourglass
Adventure:
Broken Sword: The Shadow of the Templars - Directors Cut
Hotel Dusk: Room 215
Phoenix Wright: Ace Attorney (3 other from the Ace Attorney series currently avaiable)
Professor Layton and the Curious Village
Building Sim:
Anno 1701: Dawn of Discovery (or Anno: Create A New World)
SimCity Creator (or SimCity DS)
Strategy (turn based):
Age of Empires: The Age of Kings (or Age of Mythologies)
Advance Wars: Dual Strike (or
Sid Meier's Civilization
Strategy RPG (real time)
Final Fantasy XII: Revenant Wings
Strategy RPG:
Fire Emblem: Shadow Dragon
Disgaea DS
Final Fantasy Tactics A2: Grimoire of the Rift
RPG:
Chrono Trigger
Dragon Quest IV: Chapters of the Chosen
Dragon Quest V: Hand of the Heavenly Bride
Final Fantasy III
Final Fantasy IV
Mario and Luigi: Partners in Time
Suikoden Tierkreis
Puzzle, Card/Board:
Puzzle Quest: Challenge of the Warlord
Planet Puzzle League
Tetris DS
Clubhouse Games (aka 42 All-Time Classics)
Meteos
Other:
Elite Beat Agents
Soul Bubbles
Most interesting upcoming games:
Scribblenauts (September)
Professor Layton and Pandora's Box (September)
Mario & Luigi: Bowser's Inside Story (October)
The Legend of Zelda: Spirit Tracks (December)
Golden Sun DS (this won't come in the near future)
All VGChartz DS reviews
http://www.vgchartz.com/games/index.php?name=&keyword=&console=DS®ion=All&developer=&publisher=&genre=&boxart=Both&results=50&order=Score
VGChartz DS RPG reviews
http://www.vgchartz.com/games/index.php?name=&keyword=&console=DS®ion=All&developer=&publisher=&genre=RPG&boxart=Both&results=50&order=Score
