The problem with the Thunder (other than that Durant plays Lebron's position) is that they've got a lot of players who will be due extensions soon. With a new CBA coming up, it's a risky move for Lebron to go there. Even under the current CBA, it's doubtful that OKC's owner would want to be deep into the luxury tax every year (even for Lebron). Lastly, the OKC media market just isn't the type Lebron will be looking for if he leaves.
With LA, he'd be playing in Kobe's shadow, which I think would drive him nuts. Also, like a lot of the teams pursuing free agents, they potentially have a ton of holes to fill on their team, as they only have four players under contract for next year. Lastly, as mentioned, you really can't trust Donald Sterling to build around Lebron and to add the pieces that are necessary.
I think the best situation's are the ones where Lebron can play beside a superstar, while at the same time having an owner willing to spend money. I'd be shocked if he doesn't end up in one of Cleveland, New York, or Miami, with Chicago being a very outside possibility.