it is possiable the buttons are being pressed and the display is staying on. what type of case are you using? a good case if you are looking for one is the one for the BB 88xx. the storm fits and and goes into standby because of the magnet saving battery life. I have mine in one and can get about 2 1/2 - 3 days (3days is pushing it) out of my storm.
What OS are you running? Clicking the screen used to light it up and that's pretty common in a holster. .83 and .85 took that away and you physically have to push the hard buttons to light it up. I would do that if you haven't already, change your backlight timeout, and lock the phone before you put it into the holster. See if that works.
I am having similar issues. Its happened to me maybe 5 time now. Twice in the pod, battery got discharged and a few times in the holster. Try kiLling all the apps before you put it away in app switcher.
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