In a survey of 3,699 consumers conducted between Oct. 23 and Nov. 3, research director Paul Carton found what he described as a “massive breakdown in consumer spending,” just in time to spoil the holiday season for retailers in about every category — including computers.

Only 8% of respondents said they planned to buy a laptop in the next 90 days, compared with 11% a year ago. Even fewer — 6% — said they planned to buy a desktop machine, down from 8% a year ago.

“It’s not easy to increase market share in one of the worst spending environments in years,” writes Carton, but Apple seems poised to do so. Among those few consumers who plan to buy a laptop in the next three months, one-third said they planned to buy an Apple — up from 29% in September.

Apple’s (AAPL) refreshed MacBook line seems to be what’s got people opening their wallets again. A total of 7% of respondents said they intended to buy one of the aluminum unibodies over the holidays. Another 6% said they had their eye on the old white plastic MacBooks at the new $999 price point.

Only 27% of the respondents who plan to buy a desktop computer say they’re going to buy a Mac, up slightly from September, but down three points from August.

The other bright spot in the ChangeWave survey is Dell (DELL). As Carton puts it:

“Something quite unusual is happening with Dell.  For the first time in nearly three years, Dell

consumer planned purchases look positively upbeat.”

Planned purchases of Dell desktops have taken a surprising leap, he writes, increasing a full 11 points to 37%. Planned purchases for Dell laptops (33%) are up 2 points, as shown in the following chart:

Why Dell? Carton asked respondents and got several versions of the same answer: “Good value,” wrote one. “Dell has the right features, ability to customize the configuration, and good reviews. I’m not impressed with HP or any other brand offerings.”

But Carton warns that “tremendous caution” is in order when interpreting these Dell results. As he puts it:

“Importantly, consumer purchases represent less than 20% of Dell’s overall PC revenue, with the vast bulk of it coming from the corporate side — where the IT spending pullback during 2008 has had a brutal impact on Dell and other PC manufacturers. Moreover, there are no signs that the overall PC market will be improving at any point in the near future. Rather, the recession continues to pick up steam.”

From the Changewave Alliance website:

ChangeWave runs a proprietary network of 15,000 highly qualified business, technology, and medical professionals referred to as the ChangeWave Alliance. Alliance members are credentialed experts in leading companies of select industries who spend their everyday lives working on the frontline of technological change. (link)

For last month’s ChangeWave report, see “The survey that squashed Apple” — Parts 1 and 2.