Kind of surprised I was able to think of 10 favorite DS games. On the other hand, I already have 10 favorite 3DS games (including downloads, granted).

Are you some sort of clone of me? Apart from the lack of Ace Attorney 3, that's exactly what I would have put as my top 10

in alphabetical order

Ace Attorney serie: it created a new genre and elevated it to perfection. I have to take the whole bulk, cause I can't remember which episode is which. They are all on the same level of excellence though (yes even the last one!).
Chrono Trigger: well this game is almost 20 years old and it's still the apex of its genre, so what can I say?!
Flower, Sun and Rain: one of the most mysterious games I've ever played — yes it's full of annoying things and the puzzles are pratically the same thing over and over again, but I loved the plot, I loved the characters, the humor, everything.
Ghost Trick: not only it introduced a new concept, but the story is one of the best ever written for a videogame. And when the ending to a game makes you cry, you know it is art.
Grand Theft Auto: Chinatown Wars: miles better than any of its 3D incarnations. Stupid, superficial and raw like all GTAs, but this at least was fun.
Hotel Dusk/Last Window: eh, I'm a sucker for detective games, and those games had it all: great plot, great style, clever puzzles.
Jump Ultimate Stars: I've never watched an anime in my life, yet this game obsessed me for months.
Professor Layton serie: again, another serie unlike anything I've played before. As with the Ace Attorney serie, I can't really put my finger of any episode alone, each one is amazing and each one improves on its predecessor.
Retro Game Challenge: kudos to the guys who created this game for coming up with the concept and actually managed to turn it into a masterpiece.
Rhythm Heaven: a thing of beauty!

still haven't played some of the big ones like The World Ends With You, Radiant Historia and 999 though

1.the world ends with you
2.super mario 64 ds
3.pokemon soul silver
4.pokemon platnium
5.crono trigger
6.mario kart ds
7.sonic rush
8.mario & luigi partners in time-i love this more then bowser inside story and idk why BIS was awsome
9.mario luigi bowsers in inside story
10.final fantasy 3 remake
my number 1 probaly be tales of heart or tales of innocense if they came to america and i do not use emulators

In no particular order:
Mario and Luigi Bowers Inside Story
Professor Layton and the Lost Future
Ghost Trick
Mario Kart DS
Mario 64 DS
Pokemon Heartgold
Phoenix Wright Trials and Tribulations
Phantom Hourglass
Spirit Tracks
Professor Layton and the Curious Village.

This guy knows what's up.

final fantasy tactics
disgaea
lock's quest
elite beat agents
New Super Mario Bros
Harvest Moon
mario kart

haven't played DS games in while tough...time to freshen up...and buy some...many are cheap ass.
only have lock's quest and spectral force genesis in my possesion at the moment..haven't played the last one even yet...

yet...

1.Ghost Trick
2.New Super Mario Bros.
3.Pokemon Diamond
4.Profesor Layton and The Daibolical Box
5.Mario And Luigi Bowser's Inside Story
6.Chrono Trigger
7.Kingdom Hearts 358/2 Days
8.Phoenix Wright Ace Attorney
9.Mario&Luigi: Partners In Time
10.Zelda Spirit Tracks

10. Fire Emblem: Shadow Dragon
9. Ace Attorney Investigations: Miles Edgeworth
8. Kirby Super Star Ultra
7. Kingdom Hearts: 358/2 Days
6. Suikoden Tierkries
5. Mario & Luigi: Bowser's Inside Story
4. Kingdom Hearts Re:Coded
3. Ninja Gaiden: Dragon Sword
2. The Legend of Zelda: Phantom Hourglass
1. The Legend of Zelda: Spirit Tracks

thanks man, I've had a few more games since then like 999, Retro Game Challenge & The Dark Spire. Maybe one day i'll update the list.

I'd be surprised if you didn't. Those are some top games right there.

1) Animal Crossing Wild World
2) Tetris DS
3) Castlevania Dawn of Sorrow
4) New Super Mario Bros.
5) Golden Sun Dark Dawn
6) Legend of Zelda Phantom Hourglass
7) Kirby Squeak Squad
8) Mario VS Donkey Kong Minis March Again
9) Chrono Trigger (I don't like to include ports/remakes in Top 10/Top 20 lists but this is the one exception...)
10) Legend of Zelda Spirit Tracks

1. Pokemon White
2. Pokemon White
3. Pokemon White
4. Pokemon White
5. Pokemon White
6. Pokemon White
7. Pokemon White
8. Pokemon White
9. Pokemon White
10. Pokemon White

When I look for my favorite games, I look for the games I've spent the most time in and the games that feel the most fulfilling.

So in all honesty, this is my list.

1. Professor Layton series
2. Okamiden
3. Kyle Hyde series
4. Dragon Quest IX
5. FF Heroes of Light
6. Radiant Historia
7. Twewy
8. Pokemon B&W
9. Advance wars series
10. 999

Also, can anyone help me ? Im searching for a DS game for a long time. I think the main character is an old man (i think it has some relation with archaeology) + puzzle game, Side scrolling...cant remember, I just saw once.

I believe it's Henry Hatsworth.

Yes yes, It is! Thank you for your help!