Depends on how you define "rare". Just taking the size of the Universe that we know of now. A Google search says there are about 2 trillion galaxies in the Universe, and if each is, say, about 100 billion stars large, which seems to be the average... Well, even if you only have one advanced life form per galaxy, that's still 2 trillion advanced life forms. That's around 500 advanced life forms for every person on this planet.
We then have the issue with where can we find life. I remember just back in my High School biology classes in the mid 90s I was taught the conditions for which life could exist. Had to have sunlight, liquid water, a pressure range... Since then we've been constantly pushing back these limits. We're finding life, even relatively complex life that exists at great depths of the oceans and pressures, under glaciers frozen for tens of thousands of years, deep in dark cave systems, next to boiling underwater volcanic fissures and hot springs, in outer space (experiments on the ISS).
Then you have the Geo-centric view of what exactly life is - how you classify it. Take the numbers above. 2 trillion x 100 billion = a metric shit ton of possibilities for strange forms of life to evolve. I can't remember where I read it, but there was an interesting article recently about consciousness and how we still don't know how it forms and what it is. One new hypothesis is that it is tied to quantum fields, and therefore not just "locked" inside our brains. Now - I'm not going to argue here that it either is or isn't - who the fuck knows, but if it is something like that, it opens a whole new can of worms about what life exactly is. We could find microbes floating around the atmosphere of Jupiter and never know that they may be linked via quantum fields creating basically a planetary consciousness.
Personally I think that the likelihood of life elsewhere is growing. It seems to me that a couple of decades ago most astrophysicists and exobiologists were of the thought that we were probably the only outpost of life, but it would still be worth it to look - to new where the consensus seems to be that it's basically only a matter of time before we find some signs on Mars, Europa or Titan or someplace.
But that's just my two dukats.
Edit:
C
Cynical
beat me to it... lol