...anyhow. As for what's ACTUALLY going to happen, that's anybody's guess. The netbook market's entirely too new to be predictable. People like the familiarity of MS, but the release of Windows 7 is going to give Linux a cost advantage (MS pretty much gives away XP on netbooks, but don't expect that trend to continue). That already makes Linux more attractive, and putting a name like Google behind it may assuage fear of the unfamiliar.
OTOH, it's what, a year off? That's plenty of time for Windows 7 to get a foothold in the netbook market. Or Apple to enter it -- it bears noting that the "Google is competing with Apple" argument doesn't really hold water in a market where Apple is not actually competing.
But that segues into the next thing, which is that we've all automatically started talking about what this is going to mean on the desktop when in fact we may not see Chrome OS running on the desktop for years yet. (In any official, supported capacity, anyway. Hackers will have it running on desktop boxes as soon as the source or binaries are available, whichever comes first.)
As far as what its immediate impact would be on desktop release, I'm going to assume it would immediately have a mainstream market that other Linuxes don't have but wouldn't match Apple -- though again, leveraging lower costs would give people pause, especially if the economy still sucks by the time it's released (again, we could be talking years down the road here). And Google's got the cache to hire UI guys to make a product as pretty and easy-to-use as OSX and sell it on cheaper hardware.
Whether Google is actually CONCERNED with the conventional program space is a whole other matter, and really the crux of this whole thing. Google's at the center of what appears to be a transition from local apps to online apps -- now, people have predicted the shift before and been spectacularly wrong, but there's one pivotal service that HAS shifted into the Web app space: E-Mail. I'm a guy who took ten years to understand why people would EXCLUSIVELY use Webmail (of course I understood the advantage of being able to access your stuff from any computer, but I still prefer to load everything up in Thunderbird when I got home for its speed and functionality), but GMail does everything you'd expect a local client to do and it's pretty and fast besides.
Of course, past that it gets a little dicey. I'm sure there are people out there who use Google Docs, but I can't say I've ever actually met any. I don't see MS Office or Photoshop going away any time soon, and that's before you get into really specialized and esoteric shit like the legacy apps firmly ingrained into corporate culture.
...Plenty more to say on this subject but I've gotta run.