There are a bunch of different models out there, and even a bunch of bikes that weren't built as touring bikes that are adaptable for the task. So instead of talking specific makes and models, how 'bout what makes a good touring bike a good touring bike? Here are a few ideas:

• Wide gearing range, often a triple crankset and wide-range cassette.
• Ability for the frame and fork to take wide tires (28 mm and up), racks, and fenders.
• Long wheelbase and relaxed frame/fork geometry. You want a stable, predictable bike -- not a 'twitchy' racer.
• Long chainstays so your heels aren't kicking your panniers.
• Reliability and field serviceability. (Hence why downtube and friction shifters still have a following in the tourer crowd.)
• Comfortable fit, including handlebars that provide multiple hand positions and a comfy saddle.
• Strong wheels, generally 36-spoke or more.