Simply one of the best Roleplaying games around, if not it.
It is superbly amazing in it gives you the possibility to do just about everything: from the creation of your character to every dialogue, there are choices to be made that can affect considerably the direction the game will take. Once, as a thief, I tried to brake into a house to steal something, just to find a Lich waiting inside, that easily eradicated my party. This may not seem much, but it's something RPG players all around can recognize and appreciate, as the game really gives you the feeling that you're playing with a GM and are capable of every choice.
Simply one of the best. Period.