Given the amount of galaxies, star systems and planets. I would say there's millions/billions Earth-like planets.
If we're talking about extraterrestrial life - definitely. Remember that Earth atmosphere is not the only one capable sustain life. Life can exist in extreme conditions and what's extreme for us, don't have to be extreme for something/someone else.
We are carbon based life form right? Every single living organism on Earth is carbon based. What if there's life form based on some other element? Wouldn't that be awesome?
As for intelligent life, that's complete different story.
I'd just like to point out again that the conditions that life arose under on this planet would be extreme for us. Once you have life, any life, it tends to shift the conditions towards being able to sustain even more life (even if you have situations like the "oxygen poisoning" event that killed of most life until some arose to take advantage of it).
"To have a lot of advanced life it's vitally important that !@#$ happens" <- quote from somewhere
As for non-carbon life. It's actually not too likely. This is down to chemistry, as carbon very willingly bonds into chains. It's sort of a .. ehm.. %^-* of an atom that ain't very picky about what it takes along. Thus it allows for alot of random chemistry to happen if the materials are around (and if there's a reasonable amount of heat that's a pluss too).
Silicon based life is hypotethically possible, but much harder to pull off. Though life based on silicon might be capable of popping up under conditions that wouldn't let carbon based life happen.
Though my bet on the most likely life we would ever be to meet would be robotic or some techno-organic hybrid. Ie, what a very advanced civilisation, that couldn't simply ignore Einstein, would create to explore the universe.