Gartner predicts that the price differential will not come down in 2007 and might not come down in 2008, depending on the prices of screen digitizers, the technology behind the screen that turns a touch from a finger or a stylus or the electronic impulse of a special pen into data that can be stored.

Fiering said that digitizer prices have proved "remarkably stubborn" and have not dropped as components tend to do in the PC industry over time. Part of the problem is that suppliers have not geared up for massive production, held back by fears that the market might not do as well as predictions, Shim said.

Even with higher prices, tablet PCs have sold a little better in vertical markets than earlier predicted, said Roger Kay, an analyst at Endpoint Technologies Associates Inc. in Framingham, Mass. In settings such as health care or manufacturing, tablet PC users have found using a pen or a finger to check boxes on a standardized form is easier, eliminating the need for the keyboard, he said.

The leading applications that benefit from a tablet PC are for clipboard replacement and handwritten annotation, Fiering said. Filling out forms for inventories, surveys or patient care has proved the most popular.

Also, insurance adjusters, contractors and students can use tablets to take notes. For example, nontext input for college chemistry or math majors who use symbols and formulas has been popular, Fiering said. Note-taking is also important in work situations. Salespeople and doctors, for example, must interact with another person, keeping eye contact while writing instead of typing on a keyboard.