Russell's "History of Western Philosophy" is a wonderful book, but I am told by people more expert in the history of philosophy than I am that it's not terribly accurate. I don't think that's much reason not to read it, but treat knowledge acquired from it with caution.
(Allegedly Anthony Kenny's big single-volume history of philosophy is more accurate and also enjoyable to read. I have it on my shelves but haven't opened it yet, so can't confirm or deny that.)
Yeah, I was advised to bear in mind that it was very much coloured by Russell's take on things.
In some ways, I treat it like a wikipedia article -- a mostly-good overview, which can be used as a guide to look up more rigorous accounts of any particular topics that interest you, but is kinda biased. But it's better written than wikipedia, and I'm more interested in Russell's bias than a random netizen's ;)
(Allegedly Anthony Kenny's big single-volume history of philosophy is more accurate and also enjoyable to read. I have it on my shelves but haven't opened it yet, so can't confirm or deny that.)