As there are often discussions about grammar in the comments, I thought I’d throw out one of my favorite rules, inviolate to me, and let you guys duke it out:
The serial comma (also known as the series comma, Oxford comma or Harvard comma) is the comma used immediately before a grammatical conjunction (usually and oror, sometimes nor) preceding the final item in a list of three or more items. For example, a list of three countries can be punctuated as either “Portugal, Spain, and France” (with the serial comma) or as “Portugal, Spain and France” (without the serial comma).
Opinions vary among writers and editors on the usage or avoidance of the serial comma. In American English it is standard in most non-journalistic writing, which typically follows the Chicago Manual of Style. Journalists, however, usually follow the Associated Press Style Guide, which advises against it. It is less often used in British English. In many languages (e.g. French, German, Italian, Polish, Spanish) the serial comma is not the norm – it may even go against punctuation rules – but it may be recommended in some cases to avoid ambiguity or to aid prosody.
Like Strunk and White before me, it was, is, and always shall be “red, white, and blue.”