I picked up a Navigon 2100 GPS for $120 off of bensbargains.net last month. This is the least expensive GPS that I know of that will read the street names to you. Other low-cost models just say "turn right", "turn left", etc. Some online reviews said that the Navigon has a slow user interface, but I didn't think it was bad at all.
Two unique Navigon features are lifetime free map updates and an awesome highway interchange mode that makes it easy to determine which lane you should be in. It also has an excellent three-dimensional "reality view" which is extremely intuitive.
This unit pretty much does everything that I would want a GPS to do. Some more points of interest would be nice, but at this price point, I really can't complain! Highly recommended if you are in the market for a GPS unit for your car.
Update: Oops, my bad. Turns out the Navigon doesn't have free map updates after all. It does have free software updates, but probably most of the other GPS manufacturers offer that also.