I've only heard of Abeir-Toril (Forgotten Realms), Middle-Earth (The Lord of the Rings) and Azeroth (World of Warcraft), but only liked Abeir-Toril.

I don't like The Lord of the Rings. I can't stay awake during the films, and I'm not even going to think about reading the book. I've never played Warcraft, but I've heard of the world it's in.

So Abeir-Toril it is. I played Demon Stone and Baldur's Gate (can't remember which one - it was at my uncles house), and have yet to read the novels.