I use a fair amount of butter, so this blog post from Kurt Harris on the meaning of paleo resonated with me. Lately I've been getting goat butter because it has proportionally even more short and medium chain triglycerides than cow butter, and less MUFA and PUFA.
http://www.paleonu.com/panu-weblog/2010/3/28/the-only-reasonable-paleo-principle.html