I would recommend the 436 also. You can do a basic programming in a few minutes by entering your ZIP code, and selecting the categories of traffic (AKA Service Types) you want to hear. You can get much more in-depth if you make your own Favorite Lists, but doing so is optional.
Uniden offers an external GPS solution for $70-80 online. It includes the GPS receiver, a funky Y-cable that connects between the scanner, a 12V outlet, and the GPS receiver, and an adapter cable for connecting the Y-cable to the 436 and other handheld scanner models. It works, but you have a clutter of cables and it's not convenient to use if you're riding a train or bus or in a friend's car and want to listen to the scanner as you go.
As an alternative to the Uniden solution, I offer installation of a GPS receiver inside the scanner. It has the advantage of working wherever you take the scanner without any extra wires or power plugs needed, but has the disadvantages of voiding the warranty and reducing the battery life slightly when the GPS is turned on (if you are running the scanner on batteries). The threads in the previous post have more information about this option, particularly the second one, or you can PM me.
With either GPS solution, the scanner gets its current location from the GPS. It continuously compares its current location with entries in the database or favorite lists being scanned, and automatically turns on things that are nearby matching the Service Types you want to hear, and turns off things that are too far away to be received. With the main database, you can travel anywhere in the USA and Canada, and the scanner will continuously update what it monitors, so that you are always listening to local traffic as you go.
If you will never travel with your scanner, then GPS is not necessary. You can enter your ZIP code or your lat/lon coordinates to tell the scanner where it is located, and the scanner will continue to use that location until you manually enter a new location, or the scanner gets a location from a GPS.
If you choose to purchase a 436 or other scanner, you've already come to the best place for assistance learning how to use it.