By Becky Waring

Do your part to save the planet and invest in a Global Positioning System (GPS)—avoid printing out countless pages of directions and wasting precious gas by making useless wrong turns. In the long run, your bank account will thank you too—this is one long term digital investment worth spending the up-front money for.

With a GPS display, you can view and hear turn-by-turn directions that make it a snap to get from point A to point B. Some can even account for current traffic conditions if hooked up to your cell phone, helping you avoid accidents and jams.

In addition to directions, they include databases of gas stations, restaurants, hotels, ATMs and more. And if you travel overseas, you can usually buy an extra map card to swap out the US data temporarily.

While navigation systems are available options on many cars, the built-in versions are generally much more expensive than portable units and can't be taken with you when you travel.

Alas, here are four top handheld and in-car GPS systems that won't steer you wrong.

For getting around either on foot or in a car, a GPS Smartphone or add-on is your best bet. The BlackBerry Curve 8320 has Wi-Fi and a BlackBerry Maps software that gives directions and integrates with your address book—just click on an address to get directions. You can use the mapping software on its own, or integrate it with an add-on GPS receiver.

Windows Mobile and Palm Treo devices have similar software and add-on receivers available. The new AT&T Tilt sports both built-in GPS and Wi-Fi, has a large touch screen and a full slide-out keyboard.

The Rolls-Royce of car-centric GPS navigators, the Garmin nuvi 760, has a wide 4.3-inch touch screen that is easy to read. Since it also works as an MP3 player, a photo displayer, an FM transmitter and a hands-free Bluetooth speaker for your cell phone, you can fill all your automotive and tech needs with one handy portable device.