2 endings are a given. After that, it'll come down to creativity on Obsidian's part. I agree with the above poster that the ending should atleast, somehow, incorporate what you did on each planet you visited.
I know in Star Wars they usually go for the "cheesey" ending (Ewok village ending, Yavin medal ceremony ending) and KOTOR 1 adhered to that with their two endings, which is fine. But it would be cool if once you finished the game, first they showed cutscenes of what happened to each of the worlds or whatever, then they went in to a final cutscene like KOTOR1 (but longer) to fulfill the "SW ending" quotient.