It sounds like you give your battery a workout each day, so I'd say the Desire HD might just be dead in 4 hours.
Battery life aside, my current two phones are the Dell Streak 5 and Nexus S. I love the pocketable tablet experience and (for me) decent battery life of the Dell and I love the clean Android install on the Nexus S along with the pretty good camera and Super AMOLED display. Once you get used to that 5" display on the Dell, it is hard to go back to a small display though, and I can understand your interest in the Desire HD.
In several more months the HTC Sensation will be out, also with a 4.3" display running at even higher resolution. But with a large display and dual core CPU, I don't hold much hope for great battery life.