I am struggling to get a days worth of battery life out of my HTC desire.
I turn off wifi when not using it; rarely turn on GPS; use it in flight mode and I've just started using it on on request synchronisation rather than continuous updates for gmail, facebook etc
(and I don't use a live wall paper).
I've bought a spare battery which I carry round with me. For example today I was using my HTC desire and used 2 batteries during the day.
The battery is certainly not as good as the one I had on my previous Nokia smartphone.
I am using this phone more than any phone I've used previously (camera, browsing...). However, it definitely needs a better battery. The Desire is a brilliant phone. The battery is its achilles heel.