Only 5h and 20 minutes? With my n800 I was able to watch videos pretty much non-stop at work for almost 8 hours with wifi on and me switching back and forth (leaving the video running) to chat in IRC or AIM. I'd also occasionally search for something on the internet. I could get a whole 12 hour shift with periodic movies and lots of browsing/chatting. And I think with the extended battery option available I could get more than 12 hours of constant run time with power hungry tasks.