I'm not sure we are the most advanced, but I have a few points to make: I think most people like to think that humans are more advanced for the same reasons stated by Footprints (God chose us).
I am not religious, btw.

Reply to Footprints: Now we are into the philosophical arena. But I started that with the self-awareness, so I shall attempt to do a proof. So far, only humans pass the Turing test, which states that one must be able to convince a board of psychologists and other experts that you are intelligent. This is a not complete test however, so that makes the point somewhat moot. I can't say I am able to proove it to anyone but myself. I still think we are self-aware, though.
On the note of bacteria being able to live in 150 degrees, I'd say that there isn't a single species/race of bacteria that is currently as widespread as humans, that is, without actually living in the humans. Because, we are actually the environment they live in, they aren't very widespread in that sense.