I would say that you should wait until you're in Phuket to book. Don't book at a 4 or 5 star hotel desk. There are many, many tour companies to choose from, if you're in a tourist area.
Originally Posted by
koroleon
...do the tours pick you up from wherever you're staying?
Yes, as long as you are booking in the same general area that you are staying at. If you're staying in Karon, book from an agent in Karon, not Patong. If you're in Surin Beach, book from someone there, etc.
As for your tours:
Similan Islands - Similan Islands are open only 6 months of the year. Best rated from your list of choices. Just be aware that your visit coincides with the open months of the park.
James Bond & Phi Phi island are standard cookie cutter day tours. Great value because of the volume they do.
Elephant rides - I don't recommend the elephant rides, but many people like them. I see it as an unnecessary danger.
I have no way to tell which locations use unregistered elephants, or the condition/treatment of the animals. Like I said, they are popular. Do it if you think you'd enjoy it.
Between the Doubletree and Westin... the choice is up to you. The Doubletree is in the middle of the Surin Beach community. Westin is isolated and you may have difficulty with tour pickups at that location. It depends on your style.