If the curiosity rover find evidence of life.

[markmcdaniel]

While I also do not think such a discovery would lead to the decline of any major religions, I do think it might help chip away at the spell for more people. Religion always rotates around the idea of humans and the earth being so special, and further evidence to contradict that may convince a few more people to reconsider what they've been taught. The vastness of the universe, and the relative insignificance of our puny little planet, were one of many things that made it impossible to really "believe" for me. For the rest of you, maybe it was that or something else, but a lot of our reasons for disbelieving go back to science and empirical evidence.
Yes, the "fundies" will make up some excuse, but most people can only tolerate so much bullshit before it all spills over.

I think that you are right up to a point. However, I think that the discovery of life on Mars may provide a major blow to the Judeo-Christian-Islamic tradition. Humanity has already been removed from the center of the universe. Now humanity would be separated from it's special creation. I do not doubt that the theist will try to rationalize, at least those who don't simply deny , the new reality. It will still be a major blow to a literal interpretation of their sacred texts and thus will force them to think. At least i hope this will be the case.