With the latest Anthrax 3.2.1a kernel, my battery drains a little faster than when I was on 3.1.8, but not by much. I've been off the charger for a little over 2 hours and am still at 99% battery, so it must be something on your phone that's not letting it go into deep sleep mode. Install Better Battery Stats from XDA , that should give you a rough idea of where all your battery life is going.
Also, check your Battery Use section in Settings to see what's using the most battery.