...Spirit will not find evidence implicating liquid water with Gusev Crater and Opportunity's evidence of past liquid water at Meridiani Planum will be suggestive but inconclusive. I also expect that Mars Express will find plenty of subsurface ice, but nothing suggestive of large liquid acquifers.

My own view of the evidence to date is that Mars has always been cold and dry, punctuated by brief and catastrophic periods of flooding, triggered by either impacts or volcanic activity. I suspect that CO2 and cathrate flows have formed some features, but not nearly as extensively as Hoffman suggests.

Those are my predictions, but I would sweat it if actual results showed something entirely different.