If you buy a Garmin, choose a model that ends with a "5", like 205, 255, 265, 755, or 765, etc. They are newer models than the ones that end with "0" like 200, 350, 360, 760, etc.
There are several useful upgrades from the older series to the new series, so be sure you get the latest. Within the new series, as you go up in price, you get more features like widescreen, mp3 and bluetooth, but the basic navigation is the same.
Check here to see differences between Garmin models:
https://buy.garmin.com/shop/shop.do?cID=134
Tom Tom also makes good GPS but I am not very familiar with their products.