I've disabled all push notifications for apps I don't care about, but there are some I do indeed want to receive notifications for. I turned off Google Now and some Google account syncing - basically everything that isn't gmail. I've had most of the stock apps turned off since day one - geonews, flipboard, allcast, etc. I don't have any of the fancy features like air gesture, NFC, smartstay, etc.

I think I've managed to turn off absolutely everything that I don't actually use. I'll test the battery life, etc, but I still think I'm going to root my phone!