Well, the title basically asks by itself.
Here's my list:
System Shock 2
Baldur's Gate II
Star Wars Knights of the Old Republic
Betrayal at Krondor
Mass Effect (I don't consider Mass Effect 2 to be really an RPG)
Is that a joke, or are you really serious?
I like to ask, how many RPGs have you played before Mass Effect 2? (Other than MASS EFFECT 1)
But, I wouldn't call it a pure shooter either. Like I mean, It could be called a "hybrid" or shooter-rpg, or shooter-interactive story, shooter with rpg elements. Or something else. One name leaves the rpg out. So i think it walks a fuzzy line. And thats the problem with trying to categorize some games.
Just my personal opinion. And I love the game. But OT i already listed mine.
Edit: I just bought planescape torment. Hopefully I'm not dissapointed in it, like I was with "the best JRPG/RPG ever" it's name is a secret to avoid disaster.