I'm one of the lucky ones. My yellow beast so has excellent battery life. I take it off the charger at 5 am. Use it throughout the day. I'm not a hardcore user, but I do constantly check emails, reply to various texts, listen to music on my commutes, etc. No gaming. When I go to bed at around 10:30 or so, I still have around 35% left. Not awesome. But not bad for such an old phone.
And was it that way from the start? Have you tweaked any settings or just run out of the box?