[VTDragon]

I've got a Garmin Nuvi and liked it very much. I subsequently got a Droid Incredible phone and played a bit with the Navigator app built into it. I found that it was actually better than the Garmin I had since it actually spoke the street names where the Garmin version I had did not. Then I bought a Ford Edge with built in navigation and found that was even better yet as it gave better detail of the road ahead at turns.

I think you will be happy with either Garmin or Tom-Tom. Preference seems to be based upon what you get used to, as each works slightly differently. Whichever you chose, be sure to get the version that speaks the street names as this is very helpful when in unfamiliar areas. Don't forget that the various smartphone apps ar also viable alternatives.