Five years ago I said I wanted my GoogleOS. Maybe I'll see it next year.
This could be huge. It could overtake Linux on the laptop in less than two years if done properly with good licensing. Ubuntu has done a good job making Linux-with-Gnome a desktop environment as stable as Windows XP was, but I suspect that Google Chrome OS will be at least as good as that from day one. As long as the set of initial work tools is good, Google's lack of half-baked, never-finished Gnome-based apps will actually help it, not hurt it.
If done well enough, it could hurt Apple if a $700 would-have-been-Windows laptop has the same ease of use and shininess and stability as a $1200 MacBook (and ditto for a $1100 / $1800 split for the higher end). For many PC users, Google's brand impression is better than Apple's; if nothing else, this could dampen the rate of switching.
I am excited, to say the least.