Finding the best GPS system is like buying the perfect car. It's all relative -- to you! The perfect car for me would have to be able to survive two rowdy kids, a dog, sometimes two cats, and a wife who routinely picks up junk (Oh, excuse me, they're called collectibles) on the side of the road. It would have to be roomy and maintenance free. For someone else, the perfect car would only need two seats, a rag top, and be able to do 120 mph easily.

In order to find the best GPS system, you have to first understand what they generally do and what are the usual features, then define what you want it for.

By GPS systems, I'm specifically talking about the after-market car variety. You know, the kind you see perched on people's windshields at the grocery store. I'm not talking about the in dash kind that come with some cars, nor am I considering the hand-held varieties you would take on a long hike. The after-market systems are usually called portable GPS receivers, or systems, and that's what I'll call them here.

Basically, all of these portable GPS receivers do exactly the same thing. They show you where you are on an electronic map, and they tell you how to get where you want to go, be it down the street or somewhere across the country.

All GPS systems work off of the same network of satellites that ring the earth, and most of the portable ones even use the same types of receivers. So, the differences between makes and models are not in how they work or what they do, fundamentally, but in the bells and whistles that come with them.

Virtually all GPS systems come with the following:

* Voice prompts that tell you where to turn

* Touch screen

* Large database of "Points of Interest" (locations of hospitals, ATMs, McDonalds, etc.)

* Choice between 2D "map view" and 3D "bird's eye" views

* Automatic route calculation

* Choice between shortest and fastest routes

* Come preloaded with maps of the 48 states

The main optional features to consider when buying a GPS system are these:

* Does it actually say the names of the street you need to turn on as you approach it?

* Do you need a widescreen version (4.3-inches diagonally as opposed to 3.5-inches)?

* Do you need maps of Canada, Mexico, and/or Europe?

* Does it support Bluetooth technology, which allows you to use your GPS system in conjunction with your cell phone to make hands-free calls? (Which essentially makes it a windshield mounted version of those little ear clips people walk around with.)

* Can you enter multiple routes into the unit and have it calculate the best route to get to all of them? Say you were in an unfamiliar city and you wanted to go to the cleaners, the grocery store, the movies, and a local dentist all on one trip. Could the GPS system calculate the shortest possible route to get to all of these?

* Does it have real-time traffic and weather report capability, and can it use that information to re-route you around traffic jams?

* Can you use your device to listen to music (mp3) or to look at digital pictures?

* How big is the Points of Interest database?

There are a few other features that major manufacturers include. Magellan, for instance, has hooked up with AAA to offer their Tourguide information actually on the GPS itself. Tom Tom has this neat feature where users can make map changes and upload those to Tom Tom's computer database which makes them available for everyone else. And Garmin is coming out with a new unit in 2008 that will learn to recognize your voice so you can enter commands by speaking instead of typing on the touch screen.

So, in order to find the best GPS device for you, you need to first decide which of these optional features are necessary, and which you might like if you can afford it.

You can get a basic GPS system for under $200. The Garmin nuvi 200, for example, has all of the basic features I listed above. It comes preloaded with regional maps (not the entire United States). If you want to spend slightly more, how about the Tom Tom One, 3rd edition, which at the time of these writing (early '08) costs slightly less than $200 at Amazon and comes with real time traffic capability and Tom Tom's MapShare (where you can uploaded changes).

Virtually all of the Magellan Maestro series is currently in the $200 to $400 range. You can get the more basic 3210 for around $250, which has millions of points of interest and, of course, the AAA Tourbook, or you can spend about $100 more and get the 4250, which includes all that the 3210 does and adds Bluetooth, voice recognition, and real-time traffic.

One of the most popular units is the Garmin nuvi 350, which does all the nuvi 200 does, but includes Garmin's "Travel Kit", mp3 capability, picture viewer, world travel clock, calendar, and more.

Deciding can be difficult, but don't put off buying one, though! GPS systems are great. Once you have your first one, you'll wonder how in the world you got along without it.