Morrigan from DA is on my list too....i luv a girl with an attitude.

GlaDOS and Core1 from Portal 2 more recently. How can you not get "attached" to NPCs throwing abuse at ya throughout an entire game ?
Minsc from Baldur's Gate 2.
Standing out though, even after all these years, is Dr. Marie Delacroix from System Shock 2.
A NPC who briefed and guided you through the early part of the game via comms.
She was trapped in her office and i was to get to her and set her free.
So, for hours and hours i gunned, lockpicked, computerhacked and sneaked my way up through the lower decks of the "von Braun" under her guidance.
Now, SS2 was a game that had many people creep out to begin with. You really got a sense of involvement....the term immersive barely covers it .
Of course i finally made it and entered Delacroix' office....only to find her dead in her chair !!
Gutwrenching....i'll never forgive you for thatone, Irrational Games

(unless you give us SS 3 !!)
I'm a guy with both feet solidly planted on terra firma, but in that moment a computer game got to me.
o/