Further recommendations from own library:
Advance Wars: Dual Strike
Age of Empires: The Age of Kings
Anno 1701: Dawn of Discovery
Castlevania: Dawn of Sorrow
Clubhouse Games
Dragon Quest Monsters: Joker
Elite Beat Agents
Final Fantasy Tactics A2: Grimoire of the Rift
Hotel Dusk Room 215
Tetris DS
Kirby Canvas Course
Mario & Luigi: Partners in Time
Meteos
New International Track and Field
Orcs & Elves
Phoenix Wright - Ace Attorney
Phoenix Wright - Ace Attorney: Justice For All
Picross DS
Soul Bubbles
Space Invaders Extreme
Undercover: Dual Motives
Metroid Prime Pinball
Other recommendations (which I haven't played):
Nintendogs
Dragon Quest Heroes: Rocket Slime
Castlevania: Portrait of Ruin
Mega Man ZX Advent
Bangai-O-Spirits
Metroid Prime Hunters
New Super Mario Bros.
Super Mario 64 DS
Sonic Rush
Sonic Rush Adventure
Yoshi's Island 2
Kirby Squeak Squad
Bleach: The Blade of Fate
Jump Ultimate Superstars
Etrian Odyssey
Etrian Odyssey II
Lunar Knights
Pokémon Diamond & Pearl
Rune Factory
Summon Night: Twin Age
Advance Wars: Days of Ruin
Sid Meier's Civilization Revolution
Animal Crossing: Wild World
Harvest Moon: The Island I Grew Up
Professor Layton and the Curious Village
Phoenix Wright - Ace Attorney: Trials and Tribulations
Planet Puzzle League
Trauma Center: Under the Knife
Secret Files: Tunguska (but I think the Wii version is better)
And these and the others already mentioned above are just the recommendable games that are already released...
Famous thread about this topic (also includes upcoming games): http://www.neogaf.com/forum/showthread.php?t=222049
