We all love anecdotal evidence, and mine is 100-275MB/mo on wife's phone (Blackjack II) who is mostly email and lots of facebook, while my iPhone 3G usage is 500-1400MB/mo and I am definitely a power user (casual online games, push email for work, lots of internet referencing, and even RDP and some SOCKS tethering when on the road). This is over the past 14 months, so I suggest those freaking out to at least take a peek and see if they will actually be affected.