I just got Media Max with AT&T ($19.99 for unlimited). I confirmed that email, youtube, internet, and google maps all work with it. I then proceeded to call AT&T customer support to see if Media Max was covering the data that I was using on the iPhone (since regular data is $.01 per kbit

). He was NOT able to confirm any data had been used yet, but if I get charged for the data, then I will instantly kill the service, play dumb, and have them remove the data charge.
The reason Im using a regular plan + data instead of the official iPhone plan is that I need to use a special family plan thru my place at work. As an employee, we get 15% off service. If I went with the iPhone plan, it expects every phone to be an iPhone. I've got 3 lines on the account so that would be $1500-$1800 just on the hardware (ouch).
I will test to see if Media Max Bundle 200 works, or if I get charged for the data. If someone else is running a non-official data plan, please post your findings here.
BTW - my phone is using a diff SIM than what it came with. It was activated using AIsign (Online version).