aww, you took my thunder. i was about to post something along those lines, about some main areas in philosophy; logic, metaphysics, ethics, epistemology, and aesthetics.
I disagree. It's heavily tinged with populism and thus, a fascination with the academic details of no consequence. The Durant book is several thousand times better.
Let me put it this way: no serious philosopher will ever rely on WikiPedia as a resource.
while i'm not at all familiar with philosophy beyond introductory college courses on logic and ethics, and a good bit of bertrand russell, i'd like to second the recommendation of will durant. he's a magnificent, very clear-headed writer and if his presentation is anything like it was in The Story of Civilization, everyone would do himself an enormous service by reading his book.
I strongly recommend Anthony Gottlieb's A Dream of Reason for an introduction to philosophers from the pre-Socratics to the Rennaissance - very entertaining to read and not difficult to follow.