The major decision to make when selecting the best automotive GPS is whether or not you want the GPS to speak street names to you.
If you buy a GPS that does not speak street names, it will tell you in advance "turn right in 400 feet" to let you know the turn is approaching. At the turn, it will say "turn right". You must look on the GPS display to verify the street name on which you are to turn.
A GPS that speaks street names will tell you "turn right on Elm Street in 400 feet". You do not have to take your eyes off the road to read the street name. This is much safer than the unit that does not speak street names.
The GPS that speaks street names costs approximately $40 more than one that does not. This feature is worth every penny. From personal experience, I highly recommend that you spend the extra money for this feature.
A couple of other features to look for is the size of the display (3.5 inches versus 4.3 inches) and how bright the display is so it can be easily seen in bright sunlight.
Best GPS that does not speak street names - Not recommended
Best GPS that speaks street names - My recommendation
In 2007, the Garmin Nuvi 350 was recommended as the best automotive GPS. This unit was the highest rated electronics product on Amazon for 2007. It was also a Consumer Reports Best Buy.
Garmin discontinued the Nuvi 300 series product line in the summer of 2008.
The Nuvi 350 is still sold until stocks are depleted. It is still the best buy for the money with the price right at $200. The next automotive GPS to consider would be the Garmin Nuvi 255.