Just came searching for this exact issue... My Droid is rooted, so no update, but I was just talking with my fiance who complained that since updating her phone last night, the battery life has been terrible. She's away for the weekend so I haven't had a chance to actually play with the phone and see how bad it is.
I haven't noticed any change in battery life since the update. Mine still drains the same as it did before. Not sure why some are seeing a huge drainage.
Edit: I take that back! I got the 2.2.2 update on Friday and I haven't had any battery change until just now! I just charged my battery 3 hours ago and haven't used my phone that much, just a little angry birds and it's already down to 40%!!!