E-reader: You certainly don't want to schlep around a bagful of books, which is why e-readers are such perfect traveling companions. These days I like the .

Bluetooth headset: You'll want to consider both sound quality and comfort when you're selecting a headset. You probably already have one, but if not (or if you're considering an upgrade), take a look at PCWorld's comparison of .

Stereo audio cable: Many rental cars these days have 'Aux' outlets that let you plug your iPod or other portable music player directly into the radio. Buy a cable at any Radio Shack or online, and save yourself from fumbling for new radio stations as you're driving. You'll be able to listen to what you know you'll enjoy--without increasing your chances of an accident.

Microfiber cloth: The world is a dusty place; unless you regularly clean your devices, they'll accumulate grime quickly, increasing the chance that a rogue dust particle will ruin your best gadgets. A proper microfiber cloth and cleaning solution (less than 3 ounces, of course) are the only things you should use to wipe down your sensitive screens. I'm partial to the .

All-in-one plug adapter: Rather than wasting your time looking up outlet types or taking the risk of forgetting an outlet adapter altogether, throw one of these in your bag and leave it there. It will cover you for plugging in just about anywhere in the world. I've had success with the inexpensive, if unimaginatively named, , while the $30 (shown here) has the same functionality and throws in two USB ports for good measure.