I'm reminded of the book, "Rare Earth", which argues that simple unicellular life is very likely quite common throughout the universe, but complex life...not so much.
True, but when you look at the sheer scale of planets in the known universe that can possibly harbor life of any kind, the number of those likely to have intelligent life is still mind boggling.
Some scientists, armed with recent findings of extrasolar planetary systems, have plugged that data into the famous Drake Equation and have concluded that there could be as many as 12,000 planets harboring intelligent life in our galaxy alone.
I fully expect for planetary explorations in our own solar system to turn up some forms of microbial life in the next few decades. Europa is an excellent candidate for that.