I don't think the DS will be becoming extinct anytime soon. But just in case, I'm keeping my original DS and my GBA (still got Kirby's Dream Land 2 and Super Mario Land 2).

-Advance Wars - Okay if you like strategy (also kicked my butt and there's no way I'm using a guide for this)
-Alien Hominid - I didn't know there was a GBA version. But I heard it's good on the GC.
-Bomberman Max - Uhhh
-Bomberman Tournament - Uhhh
-Breath of Fire
-Capcom Classics Mini Mix
-Castlevania: Aria of Sorrow/Harmony of Dissonance
-Chu Chu Rocket!
-Crash Bandicoot GBA
-Dr. Mario & Puzzle League
-Duke Nukem Advance
-F-Zero Climax/Legend/Maximum Velocity
-Final Fantasy I/II: Dawn of Souls - It was boring to me too but I'm not a big fan of FF.
-Final Fantasy Advance - But I looooooved FFTA. Get this one and enjoy.
-Fire Emblem - Can you believe that I've never played FE?
-Golden Sun
-Gradius Galaxies
-Harvest Moon: Friends of Mineral Town - Blade's right. It's boring.
-Kirby: Nightmare in Dream Land/Kirby and the Amazing Mirror - I agree, it's easy. But NiDL is a remake of the NES version and is good for the nostalgia. Amazing Mirror is passable, though.
-Klonoa GBA
-LOZ: The Minish Cap - I liked it. Vaati's a good change from Ganon/Ganondorf. But I like the LoZ series.
-Mario Kart Super Circuit - DS is better.
-Mario vs. Donkey Kong
-MegaMan Battle Network - Don't like Mega Man.
-Mega Man Zero
-Metroid Fusion/Zero Mission
-Mr. Driller 2
-Pokemon Emerald - Only get this if you need to transfer third generation legendaries to DP.
-Pokémon Mystery Dungeon - Skip it. Not worth your time.
-Prince of Persia: The Sands of Time
-Sonic Advance 1 - Very good for those who miss the 2D Sonic (just about everyone).
-WarioWare, Inc. - Good...for about thirty minutes.