Now I've got used to the phone and Android I've been experimenting with the settings on the HD and I've found turning the 3G off doubles the battery life, much as it did with the 3GS.
I took the phone off charge about 28 hrs ago, since then I've used the phone as normal, a good few calls, but only using wireless for internetz, and I watched an hour of Star Trek 2009 which I'd recoded to max settings for the phone (looks awesome
). It's used about 40% of the battery, which is perfectly acceptable. There's a widget to turn 3G on with one touch so it's readily available if needed.
Really love the phone, though. For me it's pretty much faultless exept for the very poor loudspeaker.