Reports in The Ecologist and National Geographic reports that crows are carrying walnuts in their beaks to intersections, wait for the traffic light to turn red, drop the walnuts and after the cars run over the nuts, fly down and pick out the walnut meat. The National Geographic continues, stating that crows can make tools - and not just by accident. They create two different tools, depending upon the need. Apparently crows are as smart as chimpanzees, and studies seem to show that actually, crows are better at making tools than chimpanzees.
In addition, studies show dogs can map language. Great apes have been taught to communicate using sign language. We know that some animals can lie (recall, for instance, the article "Lemurs can be liars, if they think you want their food" in the May 2006 issue of Monitor on Psychology).
So, if planets are a natural consequence of the laws of physics (especially gravity) given a debris field, and life a natural consequence of the laws of physics and chemistry given liquid water, common basic organic molecules (found everywhere in space, from nebulae to comets), and an energy source, is sentient life a consequence of the laws of biology given a "boring" enough environment (see "Universal Biologies - Order from Chaos," and "Sentient Life" post)?
This is not to say that the universe is teeming with sentient life. While life is probably fairly common, most of it will be microbial type. Even with Earth's history, microbes account for most of the timeline for life. While catastrophic events can (and have, on the Earth) wipe out larger life forms, microbial forms are the most likely to survive.
Microbes can even survive being blasted into space; for example, if a large meteor hits a planet, large chunks of the planet can be launched into space. If one of those chunks hits another planet - life may be seeded there. Some feel that maybe that has happened between Mars and the Earth: some say life may have started on Mars first, then spread to the Earth (making Mars the garden of eden, and it did have a much wetter and warmer past), others say the reverse.
In addition, some environments are probably too harsh for large, complex life forms to evolve, or greatly slow down the evolutionary process (increasing the chances for a large enough catastrophe to set the evolutionary clock back).
But, life will find a way, and where there is life, there is hope. Thus, I believe sentient life is a natural potential - it will result if given a chance. But it won't be as common as, well, "common," or lower, life forms.
Dingfelder, S. "Lemurs can be liars, if they think you want their food." Monitor on Psychology. Vol 37, No. 5 (May 2006). 10. Can also be found at <http://www.apa.org/monitor/may06/lemurs.html> (as of 1 December 2007).
Owen, James. "Crows as Clever as Great Apes, Study Says."
National Geographic News. 9 December 2004. 1 December 2007. <http://news.nationalgeographic.com/news/2004/12/1209_041209_crows_apes.html>
Pickrell, John. "Crows Better at Tool Building Than Chimps, Study Says." National Geographic News. 23 April 2003. 1 December 2007. <http://news.nationalgeographic.com/news/2003/04/0423_030423_crowtools.html>