I'm not an educated phylosopher. I read some of the works mentioned in the school, but didn't find their phylosophy particularly inspiring.
So, my favorite is Hitchhicker's Guide to the Galaxy.
The a book filled with truth, wisdom and insights into life, universe and everything.
Then it turns all those valuable things upside down, inside out, and shows them all from an unexpected perspective.
The book through humor delves into manny important subjects, although superficially.
Most importantly, book sparks imaginaiton, and curiosity about all the things it talks about.
Few of the quotes:
For instance, on the planet Earth, man had always assumed that he was more intelligent than dolphins because he had achieved so much: the wheel, New York, wars and so on, whilst all the dolphins had ever done was muck about in the water having a good time. But conversely, the dolphins had always believed that they were far more intelligent than man, for precisely the same reasons.
So simple an idea, which spawned many hours of discussion about human race as a whole, it's achievments (the wheel, New York, wars) and values the human race holds dear.
Hitchhicker's guide about Plato's Republic, and governments in general:
The major problem, one of the major problems, for there are several, one of the many major problems with governing people is that of whom you get to do it; or rather of who manages to get people to let them do it to them.
To summarize: it is a well known fact that those people who most want to rule people are, ipso facto, those least suited to do it.
To summarize the summary: anyone who is capable of getting themselves made President should on no account be allowed to do the job.
To summarize the summary of the summary: people are a problem.
Few on the perspective on humans as the center of the universe:
Several billion trillion tons of superhot exploding hydrogen nuclei rose slowly above the horizon and managed to look small, cold and slightly damp.
She saw the whole infinity of creation (as extrapolated from a piece of fairy cake) and herself in relation to it, she saw herself as a microscopic dot on a microscopic dot lost in the unimaginable infinity of the Universe.
And much more...
Also, never forget that Hitchhicker's Guide thouroghly explains that phylosophers are only want to confuse everybody and everything so they can stay in business.
So if anyone actually tries to discover the "truth" and the "meaning", one will have phylosophers national strike on his hands.