The odds are that we'll find nothing beyond bacteria. They're the simplest forms of life that we know of (viruses don't really count). Simply due to the chaotic nature of evolution and the "relative" simplicity of bacteria, odds are that the vast majority of life we encounter will be bacteria or of a similar level. The more complex an organism, the rarer it'll be. We see this on Earth, where Bacteria, by mass and number, are the most abundant form of life on the planet.
Of course, life on other worlds might not develop like ours, but the majority of life will be simple organisms, because that's just how evolution works. Life is a series of molecular replicators, and the simplest replicators (that we know of) are molecules like RNA strands.
For billions of years, the only real life forms on Earth were bacteria. It took a long time before the other organisms evolved - and had conditions been different, they might not have evolved at all. Evolution isn't a chain of progression mandating the development of complex life - evolution is merely adaptation. If there isn't selective pressure for organisms to become more complex and compartmentalized, then life won't become more complex and cells won't become more compartmentalized.
So, the vast majority of life in the universe is probably no more developed than Archean/Prokaryotic Bacteria. Fewer planets would have slimes or eukaryotic cells. Fewer still would have anything even resembling plants. Fewer still animals, and very, very, VERY few would have intelligent species. Intelligence is not a given. Humans didn't HAVE to evolve - it was pure co-incidence and a role of the dice that we did. Random chance created us. A unique combination of selective pressure and mutations at the right time is what created the Human species. Had conditions been different, we wouldn't have arisen at all. The emergence of intelligent species is almost certainly due to nothing more than chance, and the odds are rare (There's been billions of years of life on this planet and only one high intelligent species has ever arisen on it. You do the math on how frequently intelligent organisms arise).
99.9999% of all the planets in the universe are dead balls of frozen or molten rock or frozen gas and liquid. 0.0001% of them might have conditions suitable for life. I'd wager less than half a percent of them will ever develop life (and that's really optimistic). Fewer still will ever develop any life forms more complicated than the equivalent of our plankton.
Of course, with the sheer size of the universe, even with such terrible odds, there are probably still thousands of intelligent species in our galaxy and neighbouring galaxies. Of course, with the sheer size of the universe, we'll almost certainly, CERTAINLY never find them. And how would they find us? The distances are so vast, the amount of dead planets so huge that finding another intelligent species in the universe is like trying to find a needle in a haystack - oh and the haystack is AS BIG AS THE SUN.
