Anecdotally, I really don't notice much of a difference. I haven't run a battery of tests (get it?! Hah! *audience groan*) to support that in any way, but I can get through a day with either a static or live wallpaper without noticing too big of a battery hit. What eats my battery alive regardless is display-on time, seems to be no getting around that. You use, you lose?
Thank you, thank you, I'm here all week... :P