The ending choices are really simple to make, simply pick the person who suggests the course of action. The only exception is, you can select pretty much anyone for the escort of the crew survivors. So long as you pick Legion or Tali for the hacking the gates job you're fine and make sure your rear guard is the toughest it can be.

The hammerhead rocks. I'm interested in the new character though it has to be said I feel that the lack of diversity in the character builds is a tad disappointing on the second I'd love to see all character types covered by the games characters.