I work with GPS units every day and have tested dozens of models. I would highly recommend the Cx models that peeker mentioned above. I have not been pleased with the Magellan units. They tend to be not as accurate (in my opinion) and they can be very sensitive to the type of battery used. I, personally, use a Pocket PC with GPS. That way I can use aerial photos as well as topo maps for my tracking. Give me much more detail. I would stick to a model that uses the SiRF III or MTK chipset. Much better tracking in poor signal conditions (canyons, high buildings, tree cover).