I hold the classic opinion that the finest RPGs ever made are Planescape Torment, Baldur's Gate II, and Fallout 1-2. I have already played these to the degree of memorizing them and I do not intend to attempt a re-run.
Runner-ups would be, Witcher 1 and 3, and I hated the 2nd game. KotOR 1-2, Vampire the Masquerade, Neverwinter Nights 1-2 (vanilla's were horrible but the 2nd expansions are great in both), Arcanum was nice but I do not remember much about it, Icewind Dales were fun but are lacking in RPG elements. And a special mention of Mass Effect, not because it is a great RPG but because I greatly enjoyed the setting, and how the major threat of the Reapers have been implemented in this game.