Which Camera?

I own three cameras as shown in the photo above (which was taken by my new Nexus 5, so to be accurate I really have four). But which is best?

Of course that depends upon the criteria, so lets do three reviews and then compare their strengths and weaknesses.

Note that I'm more interested in photographs than taking video so the reviews will focus on images even though all are able to record in HD.

First up the Canon 550D, then the Sony Nex-6 and finally the Olympus Tough TG-1.