The current 406 ELTs don't have the GPS data linked to them- unless you cough up an additional $2,000 or so.
For me, I'm going to wait until the GPS link is part of the ELT. It is ridiculous to think it is not an integral part of the ELT- they certainly are a part of the EPIRBs and PLBs you can buy for $700.
The 121.5 will NOT be useless. The C-130s, coast guard helicopters, search and rescue helicopters and fixed wings and fellow pilots will still listen/hear 121.5.
I'm going to keep my 121.5 until the hardware and politicians catch up. In the meantime I'll carry a cell phone and sat phone. The sat phone is an outstanding piece of equipment. It can remove a lot of anxiety over weather and worried spouses.
The Gov'ment probably has their sights set on ADS-B. With this black box installed in every cub, the Gov. will know where you are, where you've been, and might even know where you're going! If you don't show up at a destination, all they have to do is click a few times with a mouse in Virginia and Voilas, there you are. They might even be able to help the tax man out in assessing landing fees, carbon taxes, and airspace usage! ADS-B will obviate the need for ELT.
Think I am paranoid? They are already using ADS-B technology in the marine industry to track vessels and enforce fines....
Bill