I think oblivion is a terrible introduction. Not a terrible game, but a terrible intro.voetballeeuw said:Dragon Age is a great example, as is Oblivion. I'm not sure about Two Worlds II, the review scores were bad. Fallout 3 and Fallout: New Vegas are also great choices.
My favorite game out of the ones I listed is Oblivion. The main story is not great, but the guild ones are phenomenal. The gameplay could use some help, but the world is massive, and a blast to explore.
Are you playing on PC or console?
EDIT: Here are the scores for TWII
http://www.metacritic.com/search/all/Two+Worlds+Two/results
So, the PC version is much better than the console.
I suggest other Bioware games if you liked KotOR, they'll be familiar.
Try Mass Effect Series and Dragon Age (I preferred origins but as you're new to the genre you'll prolly enjoy DA2 as much as DA:O, if not more. DA:O's reception had a lot to do with nostalgia, so you may in fact prefer DA2.)
Also, give Oblivion a go, but probably not as an intro. It's really very complex and the levelling system requires you to understand it before starting pretty much before going in, whereas other games you can either pretty well learn as you go, or simply guess. It's almost impossible to make a "Bad" character in DA or Mass Effect.