I'm very much looking very forward to the Echo (though I'm not in beta).
The idea of having a
1. tiny extender device
2. low power
3. stream all your channels and content (premium, recorded, netflix, etc)
4. no rental fee
means every TV in your house (including kitchen, garage, etc), can show whatever content you want.
I have an HDHomeRun Prime, and luckily this will be compatible.