I'm very impressed with what DeLorme has done with the user interface in the newly released Street Atlas 2010. It is intuitive, a first time user can get from A to B without having to read the manual, it is touch-screen friendly, and small-screen friendly.
My only regret is it doesn't use Navteq map data. I'm in Canada, and Street Atlas doesn't yet have maps as good as others do. But to be fair, the name of the product is Street Atlas USA, and understandably DeLorme does pay more attention to the map data quality in the much bigger U.S. marker.
I just posted a brief review and a few screen shots to: Review: DeLorme Street Atlas 2010.
DeLorme Street Atlas