Good RPG's

The best RPG given what you just described that you already enjoyed, is Witcher 2. Witcher 2 does the fantasy setting in a much more visceral and more appealing way than Skyrim, it tells a more mature story than Dragon Age, and it lets you make choices that have consequences in a more realistic and subtle way than Mass Effect 1/2/3. The game has about 16 different possible endings, the peripheral characters are all fleshed out and intriguing, the animation and graphics are beautiful (far exceeding the visual appeal of any of the games that you listed), and the story is one of the most mature games ever made. And when I say mature, I'm not referring to the adult-oriented content, but to the way the game treats the player and introduces the story to the player. It never assumes that you are too stupid to play the game.
Trailer: http://www.youtube.com/watch?v=SdiK8uaduZs -------- http://www.youtube.com/watch?v=KIguEWfEJ-0 -------- http://www.youtube.com/watch?feature=endscreen&NR=1&v=Z...

Another classic RPG that is arguably the best PC game ever made (although that might be some nostalgia talking) would be Baldur's Gate 2 aka the game that Bioware made before they went toward dumbed down-choose your adventure games like Mass Effect.
Trailer: http://www.youtube.com/watch?v=QMhQxW_WQwA

A third game that I would recommend, although this is a complete dark horse, is Bastion. The reason that I recommend Bastion is because the game introduces you to the story not with cutscenes or chat bubbles like every other western or japanese RPG, but instead it lets a very talented narrator describe the story as you work your way through it, and this is a new approach for RPG gaming and in my opinion it's important to experience because it gives the game a very strong sense of itself as you play. It keeps the action going and has some intriguing ways to crank up the difficulty beyond just "easy normal hard" settings. It's a beautiful game, it's not terribly expensive, and I would say that it was one of the more satisfying feelings that I had with an RPG in recent years after I finished my first play through. It's a wonderful game and in my opinion, it had the best soundtrack of 2011.
Trailer: http://www.youtube.com/watch?v=mX48y24t9iU -------- http://www.youtube.com/watch?v=TptJHeWngJs

Witcher, Witcher 2, Morrowind, Oblivion, Skyrim, Fable the lost chapters, Fable 2, Fable 3, Bulders gate, Final Fantasy, Daggerfall, Arena, Fallout 1, Fallout 2, Fallout 3, Fallout new vegas, Knights of the old republic, Knights of the old republic 2. To name a few.

As the above guys said, Witcher series are amazing. But I really recommend playing Witcher 1 before Witcher 2, because the story continues.

Another amazing RPG I found was Deus Ex: Human revolution. The story is very nice, and so is gameplay. I loved it far more than skyrim, or any other RPG, except Witcher series  .