I haven't seen anything that bad...open the Monitor app and turn off data monitoring, that's supposed to help.
Get the Battery Calibration app (free in market) and follow its instructions to calibrate your battery now that you've changed ROMs.
The Froyo-CM7-based ROMs (the new Liquid, CM4D2, MIUI) don't have as good battery life as the GB ROMs based on the GB kernel...I've heard the .29 release of MIUI (which we don't have for the D2 yet) improves battery life, but haven't seen it yet myself of course.
For best battery life, go w/a GB-kernel based ROM like Apex or Zombie Stomped, etc.
If you like the UI/customizations in the CM4D2/MIUI/Liquid ROMs that are based on the Froyo kernel and CM, you're likely going to trade off battery life (at least for now, until further improvements occur in those ROMs). The amount of that trade-off varies...some people claim very good battery life on them, others not so much.