Garmin 96. Fits in my headset bag. 2 x AA last all day. Recently updated database, about £40 I think. The 96C has shorter cell life. What I like about it is that even when clipped to the yoke mount, it doesn't obscure any of the instruments, unlike most of the bigger bits of kit. I particularly don't approve of anything on the coaming that obstructs the view out of the window.
I've programmed in waypoints for the thresholds of our local ILS runways and it works as a DME accurate to .1NM. Cheaper than replacing the duff DME in the 172. It's a very useful distance to go for anywhere you like and it's really easy of that place is an airfield with an ICAO code.
TOO