for a long time i used a very basic GARMIN Etrex! it runs on 2 AA batteries! or 12 volt cigarette lighter plug. very basic, but surprisingly accurate. max speed was 999 Kmph!! i have only ever seen a max of 240 Kts. no map, just basic goto, nearest heading bearing info, but what more do you need when you have a map, VOR DME ADF etc et.
I have just bought a GARMIN GPSMAP 96 for $800, similar size and look to my old etrex, but with jepps database!! and fits in the palm of your hand, about the size of a mobile phone