The data, images, and evidence so far suggest that the planet has gone through some *enormous* changes in the past. I honestly believe that we will eventually find life on Mars, or evidence of life from the past. The mounting evidence of possible large amounts of sub-surface liquid water, just enforces this very real possibility that life, past or present will be found.
I believe it will and perhaps sooner rather than later. Two things that came out of the "big news release" that I find very strange. 1. Steve mentioned that the outcrop was the perfect place to find fossilized evidence of past life. 2. They did not mention anything about the possible evidence we were seeing in the micro images of the outcrop grind. Hopefully we will find out more at a later date.