I've gotta go with Morrowind: GOTY. It just never gets old for me and i never run out of stuff to do. Even if i did it wouldn't be close to the same game twice.

KOTOR2 seemed more watered down to me. Wasn't as long and in my opinion it didnt quite pack the punch of the original.

Fable: LC is awesome too. I'll go back to that one once in a while.

Yeh, i liked it quite a bit. Needs a few fix-ups and stuff but its a personal favorite.

Hopefully there's a sequal.