Look at an issue of Consumer Reports or you can join them online. They rate almost all of the GPS units. The 3 that they rate as a best buy on a budget are:

TomTom XLS $350.00
TomTom One 3rd. Edition $250.00
Garin Nuvi 200 $250.00

I'm going to get the TomTom XLS it not only verbally tells you to turn right or left like the others but also verbally tells you the street name. I borrowed my daughters TomTom One for our vacation and found it very easy to use. I'm not interested in the bluetooth or MP3 capability of the more expensive models.

comparemaster.com sells the XLS for $309.00 and theres no tax or shipping charge.

Good Luck