If they get the #2 pick, they have to take Rubio. He doesn't fill a need, but he's head and shoulders above the rest of the class (besides Griffin, of course). He's a pure PG who also happens to play good defense. I like Westbrook, but he's not a full-time PG; the Thunder can slide Westbrook to SG and pair him with a big PG like Rubio, with Westbrook guarding smaller, quicker PGs when necessary.
Ideally, you would pair Westbrook with a guard who has a good outside shot, but the only guard who fits that bill is James Harden. I'm not as high on Harden as I once was, but I also think people are making too much of his bad games in the NCAA tourney. I was really sold on Harden a couple of months ago, but I've downgraded him from poor man's Mitch Richmond to homeless man's Mitch Richmond. As much as I waver on Harden, I also don't see another guard who fits a need for the Thunder and is worthy of a #3-#7 pick.
Thabeet does make the most sense, but I'm also not sold on him. He's so long and athletic that I have no doubt he'll block a ton of shots in the NBA (a skill that typically translates well from college to the NBA), but as an overall defender I don't see him being nearly as effective. I have a hard time not seeing him get murdered as an on-the-ball defender, and offensive spacing is so much better in the NBA that he's not going to be able to just roam around and get a bunch of blocks as a help defender without giving up easy buckets. I can see him getting into even more foul trouble than Oden, who has a much better feel for the game. As much as people talk about Thabeet's upside, players don't just pick up a basketball for the first time in their mid-teens and develop into NBA stars (Olajuwon being the exception). I think he has enough potential as a defender to warrant a mid- to late-lottery pick in this draft, but I'm not comfortable with him as a Top 3 or 4 pick.
I'm not sold on Hill either, but someone will reach on him due to the lack of quality bigs in this class.
I don't really like anyone in the #3-#7 range for the Thunder, and that pick isn't going to have a ton of trade value. Then again, I didn't like the Westbrook pick at first, so I'll shut up and let Presti pull off another brilliant move.