There is a good post with the above title over at Virginia Appellate News and Analysis. Some good points on oral argument preparation. (Hat tip to Have Opinion).
I personally don't believe that oral argument serves much of a purpose in this age of lengthy briefs, reply briefs, and multivolume JAs. I'd say oral argument makes a difference in less than 5 percent of the cases. But, it's still nice to make that trip and feel like you had an opportunity to be heard.