Hybrid Units
A relatively new trend in GPS is the merging of GPS receivers with other technologies such as two-way radios and phones . There'll be more of this in the future, but for now, these remain niche products, aimed at a very small user group who make heavy--or simultaneous--use of both technologies. In my opinion, these units are overkill for normal business travel.

Low-End Units
Some GPSes can be had for as little as $90 or so, but as you move down the price ranges, you begin to lose important features: The least expensive GPSes are "nonmapping" units, meaning that they'll show you where you are and will let you plot basic point-to-point straight-line routes, but they work solely by latitude and longitude. They cannot navigate by street address or driving route (they contain no street-level databases). These units may be fine for sport use such as hiking and geocaching , but are of little or no use in normal business travel. Aim a little higher than the lowest end in your GPS shopping, and you'll probably be much happier with your purchase in the long run.

More On the Way
The next major change in GPS will happen when a new and different GPS system (Galileo ) is brought online by the European Union. The new system will offer higher precision than the current U.S.-operated GPS system, and will use signals that can penetrate deeper into buildings or in other obstructed locations where GPS is currently hard to use. The new EU system should coexist well with the current U.S. system, but it won't come online until 2008 at the very earliest.

Future GPSes, built to the joint specifications, will be able to use either the Galileo signals or the U.S. signals, or both. Older GPSes--including those in use today--will only be able to use the U.S.-operated GPS signals; but will continue to be able to use the U.S. signals even after Galileo starts broadcasting. That means that Galileo won't make today's GPS units obsolete; and that GPSes purchased now can still have a long and useful life.

Meanwhile, prices will continue to drop, and vendors will continue to add new features. That means it's a great time to consider getting a GPS; or to upgrade an aging GPS unit you may already have. For business travelers who need to visit locations away from major airports and the hearts of major cities, or who want a maximally flexible or complex itinerary, GPS is the only way to go!

What's your take? Have you used a GPS and mapping software for long trips? Do you have success--or horror!--stories to share? What online trip-planning services have you used? Where have you found GPS useful, or a drawback? Join the discussion.