A ChangeWave (http://www.changewave.com) survey of 3,171 consumers -- conducted in the aftermath of the January iPad announcement -- shows a huge wave of pre-launch demand for the iPad and offers key evidence that the Apple tablet will have a major impact on the e-Reader, laptop and home entertainment markets.

In particular, while a handful of e-Reader manufacturers – most prominently Amazon – clearly have a major head start, the survey findings show the iPad is poised to profoundly shake up this market. Among consumers who already own an eBook reader, the Amazon Kindle (68%) towers over its next closest rival, the Sony Reader (10%). But to gauge the potential impact of the iPad on this market, we asked eBook reader owners whether they would have purchased their current e-Reader if the Apple iPad had also been available.

One part of ChangeWave's survey asked "Now think back to when you purchased your eBook reader. If the Apple iPad tablet had been available at that time, which eBook reader do you think you would have purchased – your current eBook reader or the Apple iPad tablet?"

While nearly half (45%) of current eBook reader owners say they would have still bought their same device, better than one-in-four (27%) report they’d have bought the iPad if it had been available at the time of purchase.

But it’s when ChangeWave asked consumers about their planned eBook reader purchases over the next 90 days that the full extent of the Apple iPad’s impact on this marketplace becomes apparent. The survey shows the Apple iPad is now poised to capture a huge 40% of the e-Reader market going forward in the first 90 days after its launch. The Amazon Kindle ranks second in terms of future purchase share with 28%. Barnes and Noble Nook (6%) and Sony Reader (1%) are far back in third and fourth place respectively.

In other words, while the iPad launch is likely to strengthen overall ereader demand, the survey suggests Amazon and its competitors could well find themselves relegated to playing catch-up within just a few quarters if they don’t preemptively move quickly to upgrade their own e-Reader products.

The ChangeWave survey also focused on the overall potential market for the iPad among consumers. All survey respondents were presented a brief description of key features of the new Apple iPad tablet and then asked how likely they were to buy one when it becomes available. A total of 4% said they are "Very Likely" to buy the iPad, and 9% said "Somewhat Likely."

Before the launch of the iPhone, a ChangeWave survey found that a total of 3% said they were "Very Likely" to buy the iPhone, and 6% said "Somewhat Likely." In other words, the current pre-launch demand for the new iPad is greater than the pre-launch demand at a similar point in time for the original iPhone.

The ChangeWave Network is a group of 25,000 business, technology and medical professionals. ChangeWave surveys its members weekly on a range of business and consumer topics.