Many smart phones have issues with battery life. It's something of a trade off, if you want the power and features a phone like the Desire can deliver.
With a little bit of effort though, you can tweak your settings and get a decent amount of use before charging is required again. I'm getting a spare battery and docking station to charge both it and the phone, myself. I want to be able to use all the lovely power eating features this phone has without worrying about the battery. Did I say I love this phone?