I'm waiting for the Speck ToughSkin for the nano. It'll detract from the slim elegance of the nano but I want to make sure I get better shock protection over a naked nano.

Maybe the ultimate case would be an OtterBox for the nano to completely seal it from dust and rain.

I've already got my Newer Technology RoadTrip! FM transmitter + charger for my car. It doesn't use the remote connection like some of the other FM transmitters. It connects via the dock connector on the nano, charges it as well as sends out a strong FM signal. Just tune in to 87.9 FM and it works! It gets audio via direct lineout of the dock connector. Works beautifully!