Unlimited 2G data. LTE is limited to 5GB per month. I've hit their throttle before, and while it's nice that you don't go dark, it's not for normal use.
It depends. 1.5 hours of facetime will use ~1gb, and streaming 1 hour of music every day will run at 1gb over the month. Add browsing during commute and you're getting close. It's probably not "normal" in the sense of average, but for the heavy consumer, they will have to moderate their usage.