I second the Windows CE based device, I started with an IPAQ and GPS card and now have a Mio P550 Pocket PC with built in GPS and antenna. Memory Map 1:50,000 and 1:25,000 maps on the PC can be uploaded for the area needed. The battery lasts easily for 2-3 hour walks and an external battery will recharge it over lunch. Being able to down load walk routes from various websites (like walking world) is an added attraction as is the Route66 satnav software that it came with.