Steam
Bastion
Half Life 1 and/or 2
Deus Ex
Knights of the Old Republic
Braid
Don't know any of these

PS3
Mass Effect 3 (I have played the earlier entries)
Ni Nu Kuni: Wrath of the White Queen
I've only played a bit of Mass Effect 3 so I can't comment too much, but I enjoyed 2 a lot. Ni No Kuni is also good but it's very long so be prepared for a time investment!

PS2
Tales of the Abyss
Tales yes. Abyss is a really good game


PlayStation
Arc the Lad III
Haven't played any but I have heard good things about this one. Can't say from a personal point though

PSP
Tactics Ogre: Let Us Cling Together
This one so you can give me help and tips ;_;

Wii
Arc Rise Fantasia
Okami
Pandora's Tower
No More Heroes 2
Finish one of the half dozen games you started but never finished...
Haven't played any of these

GameCube
Start over on Tales of Symphonia
Start over on Skies of Arcadia
Both excellent games. I prefer Symphonia but can't go wrong with either

N64
LoZ: Majora's Mask
Second favourite game ever. Should tell you what you need to know

3DS
Bravely Default (Once you finish 4 Heroes of Light)
WE CAN PLAY AT THE SAME TIME