When preparing for a marathon or a big race, you know proper training is key. The Nike Triax Elite, a four-part digital training system, takes the guesswork out of planning your day-to-day runs, helping you get in peak shape and stay injury-free. Each of the four parts of the system is well designed, and the software is excellent, but managing the entire package requires more work than it's worth for casual runners. Plus, its high asking price might rule out all but serious athletes.

Not for the faint of heart, the Suunto X6-HR is a powerful sports watch in which hard-core trail runners, mountaineers, and cross-country skiers will find plenty to like. It combines a heart-rate monitor with an altimeter in a slick package that's water-resistant to 100 meters. In addition, the X6-HR collects and stores data for later analysis; you can view, compare, and analyze your performance using the included Activity Manager software.

If you spend a lot of time in your hiking boots, the Highgear Axis is for you. The wristwatch incorporates a digital compass, a barometer, an altimeter, and a chronograph, among other features, in an attractive and sporty package. We do wish, however, that it had a heart-rate monitor and a PC component for downloading and splicing performance data. That said, it does what it's supposed to do quite well.

Let celebrities have their personal trainers. The Suunto t6 will help you take your fitness goals into your own hands. The first in a new line of Suunto fitness watches emerging from a partnership between Firstbeat Technologies and the Finnish Research Institute for Olympic Sports, this high-quality watch aims to do everything--and it almost does. You'll have to pay a high price for its features, though.

Shock- and water-resistant to 200 meters, the solar-powered G-Shock Atomic Solar is, in a word, rugged. It's suitable for wearing while mountain biking, chilling at the beach, or trudging to a campsite. It can record up to 30 different start and stop times, as well as double as a split-time stopwatch that records two finishes. On the other hand, we wouldn't rely too heavily on the G-Shock's flakey atomic-clock-signal reception.

Whether you're a serious athlete with several Ironman competitions under your belt or a weekend jogger who sweats a 10-minute mile, the Garmin Forerunner 201 will give you a leg up on your training. This lightweight GPS device also comes with an ambitious roster of features for monitoring your pace and tracking mileage. There's a lot we liked about the 201, but performance inconsistencies keep us from awarding it the gold.

Water-sports lovers, this one's for you. The Freestyle MacDaddy displays a unique split screen and is designed to withstand repeated exposure to water with a salt-water-resistant polyurethane band, a watertight casing, and stainless-steel controls. The interface isn't all smooth sailing, however, and if you're looking for a timepiece to wear while improving your times in the pool, take a pass on this one.

The Timex Bodylink is a multipart GPS-enabled training system that delivers precise speed, heart-rate, and distance data. We found the measurements and GPS to be spot-on, and we really wanted to like the package. Unfortunately, the clunky design and the lack of a PC component really burst our bubble. If Timex issued a new version with a smaller antenna and a USB interface for uploading data to a PC, we'd be psyched.