Have a friend who works at JPL (he does testing and problem solving stuff for the last rover and has recently been working on a proposal to get another mission to Mars running). But we've argued between us for years over the potential for life elsewhere in the solar system. He's far more optimistic about it than me, but he's looking to some of the places where oceans are pretty darned likely to exist now rather than Mars. Europa and Enceladus may be the ones where things get very interesting. The more we've explored the solar system, the more assumptions about life, and what we thought allowed for it, get challenged.
Do wonder if anything has managed to survive Mars losing its atmosphere and oceans. Or even if there's evidence to be found of something which was once there.