I use about 300-400 megs a days I'm using a Treo 750 on EDGE.
Right now, I have used 1.6 GB, 3 days into the new billing cycle.
One can easily go over 5GB at this rate before the billing cycle ends if I streamed everyday, but it's not that hard to reach 2 GB in a few days (or even hours). I have seen posts where users have done more than 7 GB on their unlimited MEdia Net plans where AT&T hasn't complained.
The way I read it...unlimited is unlimited/infinity/∞ etc...not 5GB, 10GB, 100GB.
Plain and simple for me.