Baldur\'s Gate, Baldur\'s Gate 2 and Neverwinter Nights, also add Planescape: Torment to that, are very RP based, sure they follow a set story, but you couldn\'t finish it without them. The fact is you can pick your path to obtain your goals.
As already stated, Fallout and Fallout 2 are brillliant examples.
Knights of the Old Republic is very, very RP based, there are many battles, but what RPG doesn\'t have enemies to defeat. Every action you make impacts the game. I am currently playing as a potential Sith Lord, after becoming a master of the Light.
Morrowind was RP gone wrong, it was not as good as it could have been.
Pools of Radiance, The Temple of Elemental Evil, these are very RPG.
There are many that simulate P&P RPGs quite well, but lack the freedom.
Dungeon Siege disappointed me and my $85.
Edit: I eagerly await KOTOR 2.