AT&T is still lagging pretty far behind Verizon when it comes to LTE, with their actual 4G network not set to be ready for primetime for another year or two. But when it does come, expect to have to pick a tier for how fast you want your service to be.
A leaked internal AT&T document shows the carriers plans: "Speed tiers will provide LTE data service at varying rates of speed depending on the plan a customer selects, similar to land-based broadband services currently offered by ISPs. Data tiers will afford subscribers 'data buckets' of varying sizes, similar to the configuration of AT&T's current data plans."
Meh. I suppose this is what it is, but I'm not happy to say goodbye to the era of simple, unlimited data plans.