Go down the roster of top-of-the-line GPS features, and the TomTom Go 720 has them all covered: text-to-speech pronunciation of street names; the ability to play audio files from an SD Card through your car's stereo; and clear, colorful 3D maps displayed on a big screen. About the only thing missing is the high-end price -- the Go 720 retails for $US500. That's less than the cost of comparable devices, such as the $US675 Garmin Nuvi 680.

The TomTom Go 720 is ready to navigate right out of the box, as the diminutive unit has maps for all 50 states and Canada built in. The Go 720 isn't much taller or wider than its 4.3-inch screen: It measures about 4.5 by 1.0 by 3.25 inches (width by depth by height), and it weighs just under a half pound. You can choose to navigate to a specific address, zip code, or intersection; to a business or another point of interest (TomTom says that the included database offers millions of entries); or to a recent destination or one that you've designated as a favorite. You also can select your destination simply by tapping a spot on the map.

In my tests the Go 720 delivered accurate directions and suggested sensible routes. If you don't like a suggested route, you can use the device's nifty 'Find alternative' option, which lets you see another route; unfortunately, though, you can't see estimated travel times for the alternatives, or any other ways to assess them. One complaint about the Go 720: Sometimes the device issued the spoken driving directions late, especially in areas with many street intersections (a fault that the Garmin Nuvi 680 and many other GPS units share, regrettably). On more than one occasion I heard the instruction to turn when I was already entering the intersection. The on-screen directions appear much earlier, however.

While the Go 720's built-in speaker is loud enough for you to hear driving directions over road noise, the instructions are much easier to hear when they stream through your car stereo via the device's FM transmitter. You can navigate while listening to audio files on an iPod (connected via an optional $30 cord) or an SD Card -- the audio pauses automatically to broadcast your driving directions. Other nice touches: You can set the device to warn you when you're driving over the speed limit (or faster than a speed you set yourself), or when you're driving near schools or places of worship. You can also choose to be reminded to take breaks at set intervals.

GPS aficionados will find plenty of extras to keep them occupied as well. Start with the free TomTom Home software, which lets you customize your maps and share them with other TomTom users, as well as download maps that others create. For example, if you encounter a street that's marked on the map as a through road but actually dead-ends, you can update your map, send the update to TomTom's site, have the company verify the change, and then make your amended map available to other users.

You can also download new voices, including those of celebrities, though most of them cost extra. You'll also have to pay more to get real-time traffic and five-day weather information. You can access the traffic service from your cell phone for about $50 a year or from the company's $100 RDS-TMC Traffic Receiver, which includes a one-year subscription to traffic information.

If you can do without the traffic information, the Go 720 offers all the features you'd expect in a GPS, and then some. The high-quality maps, clear interface, customization options, and other extras make the device a joy to use. If you're looking for top-of-the-line features at a relatively affordable price, the TomTom Go 720 is well worth considering.