Let's not mince words: A smart phone—iPhone, Droid, Palm Pre, or BlackBerry—a computer, only smaller. Is it big enough for you? Consider your own hardware and software: your body and brain.
How's your eyesight? Your manual dexterity? For all their ability to zoom in, smart-phone screens measure no more than 4 inches—the long way. Peering into one, touching tiny buttons or icons, and executing a finicky finger dance of swipes and taps could frustrate anyone.
Are you primarily a communicator, a consumer, or a creator? That will help determine the right device for you. A communicator could be content with "just" a smart phone. An avid consumer of visual media might crave a bigger screen (and, to make calls with Apple's tablet-size iPad, would need a voice-over-Internet service such as Skype or Vonage). But a creator will need a full-fledged computer to display, manipulate, and store files.
*This technology guide was written by George Blooston, Peter Brown, Ron Burley, Ty Burr, Tim Carman, Annie Gottlieb, John A. House, Sharon Kay, Dolly Setton, Abby Stokes. Consulting editor: Peter Brown.