Moto X just received a price cut last week itself and now it seems that AT&T is devoted to make all its customers happy. Moto X is available for $479 for a 16GB version now and $529 for a 32GB version but this is for AT&T only. Also keep in mind that the Moto maker tool is exclusive to AT&T so you might want to go for a Moto X now if you ever wish to.
If you wish to use another carrier then the old prices for T-mobile & Verizon customers will have to pay $599 for a 16GB, while Sprint treats you for $50 less and 16GB version costs $549. We hope your carrier gets into the discount mood soon.