I use a Garmin Edge 800 on my bicycle. I typically charge it every day, but I usually have around 50% battery left at the end of each do so it could probably last for two days of riding.
On the motorcycle, I'm currently using my iPhone 5 in a RAM mount. It connects to my Sena SMH10 bluetooth communicator so I can hear directions and prompts. This setup is far from ideal, but given that I already owned the Garmin and Sena at least it was cheap! I'd love to own one of the Garmin Zumo motorcycle-specific GPS units, but since most of my moto rides are local and I rarely use GPS I can't justify the cost. If I were using the motorcycle to tour rather than the bicycle that might change.