Wii (not counting VC games):

1. Super Mario Galaxy

2. The Legend of Zelda: Twilight Princess

3. Wii Sports

4. Super Smash Bros. Brawl

5. ??? Super Paper Mario maybe?

DS:

1. New Super Mario Bros.

2. Electroplankton

3. Planet Puzzle League

4. Picross DS

5. Pokemon Diamond 

Wii

Mario kart Wii
The legend of Zelda Twilight princess
Metroid prime 3
No more heroes
Wii sports... hum no Super mario Galaxy

DS

New super mario bros
Phantom Hourglas (Zelda)
advance wars Dark conflict
Castleania portrait of ruin
castlevania down of sorrow

i dont have a ds so i will only put wii games,also to note i dont own SSBB and MKwii yet

1.SMG(im not finished yet with this but its my fav wii game)
2.LoZ:TP
3.MP3
4.RE4:WE
5.wii sports

Wii

1) The Legend of Zelda: Twilight Princess
2) Super Mario Galaxy
3) Mario Kart Wii
4) Metroid Prime 3: Corruption
5) Zack and Wiki: The Quest for Barbaros' Treasure

DS

1) The Legend of Zelda: Phantom Hourglass
2) Pokemon Diamond/Pearl
3) The World Ends With You
4) Mario Kart DS
5) Sonic Rush

Wow making the DS list made me realise how many great DS games there have been so far. SR: Adventure, NSMB, Metroid Prime Hunters, FFIII etc. No doubt wii is going to be the same given a bit of time, I think this might be my favorite generation so far (easily is for handheld).