My wife is a new macbook pro owner and was complaining about her battery life... only getting 3 hours or so.
I looked at what she was doing and saw 2 flash videos being streamed, 2 more being buffered and she was rendering something in iMovie. Her fans sounded like my leaf blower.
i'd be more worried about the macbook's battery life than the 3 hours your wife is getting.....
her fans are worry some too.............