Author Suzannah Windsor Freeman of the Write It Sideways blog comes down on the side of the serial comma, occasionally attributed to Oxford or Harvard for some reason.  She quotes Mignon Fogerty (AKA “Grammar Girl”), who points out that the alternative to the serial comma standard is really no standard at all because you still occasionally need it for clarification.

I’m with them.  It is much more reasonable to simply have a rule rather than justifying every pre-“and” comma on an ad hoc basis.

And, the argument that you don’t need the serial comma before “and” because the commas are stand-ins for the other “ands” is, to be blunt, ridiculous.  Next time you see or hear a series of items, try imagining “and” between each one and see how literate it sounds.