There is a lot of misinformation in this thread that needs to be addressed.
1. AT&Ts unlimited isn't just for directv customers. You can also have Uverse TV service and qualify. This is welcome news to the original poster.
2. AT&T doesn't throttle after 22GB, they de-prioritize your data. Your speeds are determined by traffic on the tower you are connected to at any moment. 99.9% of the time you will not notice any difference and if you are connected to a congested tower your speed will not be 128kbps.
If you are a directv customer and are past your cheap introductory offer, you deserve unlimited data!