It's going to be another year of desktop Linux talk. (Chart from Yahoo finance.)
Personally I think there are two desktop markets, the business and the personal. Desktop Linux adoption in business will be driven by the same forces driving it on the server, namely cost and the greater control it gives the re-seller.
In the consumer realm, you need a consumer electronics player to push a complete solution, and Linux still doesn't have one. Scaled PC suppliers are still wedded to Microsoft, and aren't willing to go back to the 1980s in terms of software support or help lines. (The economics prohibit it.)
No, among consumers I suspect this will be a year of lost opportunity. I believe Apple will pick up that disgruntled anti-Vista market share. They can now scale production to meet demand, their costs are in line with the Windows desktop brands, and they deliver what consumers now expect, a complete solution including applications.
If you want to bet against Vista this year, ignore the stratospheric P/E and buy Apple. Ooops, looks like Wall Street already has. (The chart shows the relative performance of Apple and Microsoft stock since the start of 2005. The red line is Apple.)