Everything in my bob is single task AA powered with a couple sets of low self discharge NiMH, a few spare and a pack of alkaline.
This is all real survival gear, GPS, scanner, radio so I want it more reliable and standardized.

My EDC where size and weight is a concern I have a combined cell phone, music player, camera, etc with its propritary battery. Thats where I make the exception, I can't carry all those all the time and you can't find a cell phone that runs on AA's like you can a gps or digicam.

My bob gear is for more long term, when we have to bug in or out for a longer length of time where the gear may be used more and need a battery re-charge.

The combined gear I edc isn't as critical, if I can't listen to music then no big deal.