The latest research from Nielsen indicates that the Apple iPad has 82% of the tablet market in the U.S., with 43% owning the Wi-Fi version and 39% owning the Wi-Fi + 3G version. The rest of the field--Motorola Xoom, Samsung Galaxy, and others--combined take a meager 18% of the tablet market.

Apple has lost a little ground, though. When it debuted the iPad 2, Apple claimed to have more than 90% of the tablet market. It lost 8 percentage points. Samsung owns 4% of the tablet market, Dell owns 3%, and Motorola owns a pathetic 2%. According to Nielsen's numbers, 9% of the tablet market belongs to "Other."

"Despite the addition to the market of new tablet computers like the Samsung Galaxy and the Motorola Xoom in the United States, Apple's iPad is still dominating the conversation--and market," wrote Nielsen.

So far, Android-based tablets have generated little traction with U.S. buyers. Neither Motorola nor Samsung has shared firm sales figures for their tablets. One problem facing Android tablets is a lack of applications. There simply isn't a critical mass of key apps optimized for Honeycomb yet. While the number of Honeycomb apps is growing slowly, it isn't growing fast enough. Perhaps Google will have something to say about this at its Google I/O developer event next week in San Francisco.

Nielsen's study does not account for the RIM PlayBook, which may have had a successful first week of sales. Estimates place the number of PlayBoom's sold during its debut at 100,000. That was several weeks ago. RIM spent most of its energy at its BlackBerry World conference talking up the PlayBook. As Nielsen updates its data over the coming weeks and months, we'll have a clearer picture of how the PlayBook is or isn't gaining traction against the iPad.

Nielsen also looked at what users do with their tablets. It found that 35% of tablet owners who also owned a desktop computer reported using their desktop less often or not at all, while 32% percent of those who also owned laptops said they used their laptop less often or never since acquiring a tablet. Speaking personally, I use my desktop and laptop for professional reasons. The iPad has replaced my laptop as a recreational computing device, however.

The iPad has also eaten into the use of e-readers, with 27% reporting that they use their e-reader less or not at all. Nintendo and Sony should pay attention to this last stat: One in four tablet owners say they've reduced the amount of time spent with portable gaming consoles and many have ceased using them altogether.

Nielsen didn't dive into business use of the iPad.

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