So Rob,
When i hike, im always thinking of things with more than one use. If youre planning on hiking part or all of the AT, you may want a gps along for the ride. And if you like music while you walk, why then also take an iphone? This Magellan Triton 1500 Hiking GPS appears to do both. You can get topo maps by connecting to a PC, record audio files, expand the memory and add songs or books on tape through an sd card slot, hell, it even has an LED flashlight for emergencies. The best part about it? It runs on 2 AA batteries which require no charging time and can be found almost anywhere.
Just an idea.
http://www.amazon.com/gp/aw/d/B000V4S6Y2http://www.amazon.com/gp/aw/d/B000V4S6Y2