I like iGuidance best for a turn-by-turn nav program with voice prompts, though TomTom is fine too. Semsons has some nice bundle deals (software + GPS receiver). Here's
a link to their iGuidance bundles. When choosing a receiver, get one with either a SirfIII chipset or MTK chipset. They are much better than the previous technologies. If you want GPS for pedestrian use, SirfIII is generally a little better for that. ... As someone else noted, Holux is a very reliable brand of receiver. So is iTrek.