Many people swear by the Garmin GPSIII Pilot. I have the non-aviation GPSIII and it's great, for around half the price. You obviously need to enter the airfields/waypoints yourself, but in a small package you get quite a lot of functions, including moving map. You can now pick one up for around £160 or so.
I have mine set up to show the map with the following down the right-hand side;
Heading
Bearing
Time to next waypoint
ETA at next waypoint
Not to be relied upon of course, but useful as a cross-check, especially when "estimating zone boundary at time....." etc etc.
If you can afford more then I'm told the colour-map Garmin GPSMAP 295 is very good, but haven't actually used one. And I know that the 'gadget of the year' in Flyer is the new Garmin GPSMAP 196, but before anyone suggests it, I DON'T work for Garmin!
Come on you users of Magellan etc - any further recommendations?