[ZoFreX]

Bear in mind that making sure requests for static content don't send cookies is pretty far down the front-end optimisation ladder - there are normally a lot of things you can do first that are quicker, easier, and have a bigger impact.

[bwblabs]

Well another thing is that it's easier to setup GEO-ip stuff in a CNAME (so www) instead of the root A records, for now at least in PowerDNS (used by Wikipedia etc.). You're completely right, but if your sites ever scales to something big you're not in the best position with a no-www, in my view having a www record (and no-www redirect) has more benefits that a no-www.