I was a philosophy major in college, and have read a fair amount of it.
There's a real divergence between eastern and western philosophy...more that they share the same name than any of their thinking. Eastern is more into finding your "life path" so to speak (it can also be lumped into religion) and western is more about trying to prove or disprove certain aspects of life (existence, ethics, god, etc.)
I was more into the eastern stuff myself, maybe because it felt like it had more life application, but the western stuff can be interesting too.
Some good reading:
Tao te ching (there's lots and lots of translations of this, probably Stephen Mitchell's is one of the most faithful and accessible though)
There was a book I read in an entry level course that was really good...I think it was simply called "The World's Religions" by Huston Smith. He does a good job of covering everything, but I was really taken with his explanations of Taoism and Buddhism.
As for western stuff, "Zen and the Art of Motorcycle Maintenance" is a classic. Also "Thus spake Zarathrustra" by Nietzsche is a famous one, never read it though. Oh another classic is "The Prince" by Machiavelli...I guess it's more political philosophy than anything else, but it details how to be conniving bastard and get your way with things. Its definitely provided justification for selfish acts in the past.