Just a suggestion.
If you have downloaded the update for Facebook for Android, there seems to be an issue with your phone "always awake". I downloaded the update and the phone battery went south fast. I uninstalled the update and seem to be back to normal.
Comments from facebook app below
Facebook for Android - Android app on AppBrain
^^ This
After much head scratching I did some tests and I have just confirmed on my phone that the Facebook update is indeed keeping it awake. Just go into Applications --> Manage Applications --> Facebook then Uninstall Updates. I rebooted after I did that and then once back up I went into the Facebook App accepted the agreement and logged in. My EVO is now sleeping like a baby.