I just picked up a TomTom One 3rd Edition with US and Canada maps from Staples a few nights ago. It was on clearance for $120. It's a basic model with no SD card slot but has 1GB of internal memory.

The TomTom Home software works well so I am not too worried about the limited memory and no expansion because I'll almost always have a laptop and internet connection when preparing for a trip so I can buy/load maps onto it.

It's functional and inexpensive and was rated a Consumer Reports best buy at $200 ^