I'm playing a Master Transmogrifist. And I don't know what to choose for my favorite Favored Shapes.

What are the best Creatures I can choose? So far, I chose Gold Dragon and Troll. 

On high levels I can use some of the especial abilities of my favored shapes. So, What do you think are the best creatures to choose? [url=https://downloadringtonesfree.mobi/]ringtone download[/url]

The creatures must be of 15HD or less.
https://www.youtube.com/watch?v=SAmkYSzQctI