Macs aren't meant to be turned off. Mine is always either on or asleep, never off, so like someone else pointed out Chrome OS' speed is not really a selling point for Mac users who wake up their machines in a few seconds. All I see left are things I can already do + Chrome's limitations, but it's an interesting concept (for netbooks) & it will be interesting to keep an eye on. It's also not a new concept. I remember Netscape talking about making the browser the OS ~a decade ago. But I guess it's smoke & mirrors to say the browser is the OS since the device drivers, etc. are from Linux at a level below Chrome browser.
Re: the Ubuntu looks better comment... I thoroughly enjoy both OS X & Ubuntu, but come on OS X has the best UI & user experience. Sure you can make Ubuntu look like OS X. The most popular Gnome themes are the OS X Aqua themes. You can make Ubuntu look like anything you want, which is what's cool about it. Someone who is capable of discerning between (compiz) usability features & over the top eye candy can indeed customize Ubuntu quite nicely. But nothing is as polished as OS X.
Re: the Ubuntu looks better comment... I thoroughly enjoy both OS X & Ubuntu, but come on OS X has the best UI & user experience. Sure you can make Ubuntu look like OS X. The most popular Gnome themes are the OS X Aqua themes. You can make Ubuntu look like anything you want, which is what's cool about it. Someone who is capable of discerning between (compiz) usability features & over the top eye candy can indeed customize Ubuntu quite nicely. But nothing is as polished as OS X.