Planescape: Torment
 

A sinister AD&D fantasy RPG produced by Guido Henkel (Realms of Arkania games), Planescape Torment is powered by the Infinity engine that was also used in the Baldur's Gate series and Icewind Dale.
You play a scarred, amnesiac immortal in search of his identity. You awake on a cold stone slab in the Mortuary of the City of Sigil. You have no idea how you got there, who you are, or any of your past identity(s). You must escape and explore the strange world to uncover the secret of your death and rebirth…
More information.

Planescape: Torment is a story driven crpg of the so called "Nameless One" that takes place in Sigill - the center of the AD&D-Multiverse. The game has memorable NPCs like

Morte, the floating skull,
Dak'kon, a githzerai,
Nordom, a modron disconnected from its species' hive mind,
Fall-From-Grace is a succubus-proprietress of the Brothel of Slating Intellectual Lusts,
Vhailor an animated suit of armor,
Ignus, a pyromaniacal mage,
Annah-of-the-Shadows, a young and brash thief and tiefling.

Your main character - The Nameless One - has one main quest: "Who am I and why I am immortal ?" - he has to travel through Sigill, through planes, through his own mind and past existences to find answers.

The game is not combat heavy, there are some interesting factions in the game and a lot of dialog; in fact the game is like an interactive novel. Many quests can be solved by asking the right questions and giving the right answers at the right time.

If you're searching for an unique crpg with many new ideas, lots of dialog, non-standard races, interesting party interaction and a cool story - here's your game.

when you describe the characters like that, its sound familiar to the cast in NVN2 OC

More like MotB. Which takes several cues from PS:T.

This might explain why I've had trouble getting into MotB.

I still call Kaelyn-the-Dove or whatever her name is Fall-From-Grace instead.

My favourite NPC from PS:T did not make a return in MotB though: Dak'kon. Fully exploring his dialogue options as a mage with high int/wis is quite interesting.