You're saying you use gmail instead of Apple Mail? I would have trouble adapting to using a browser for email all the time. I can see it when I am using someone else's computer, but not all day. What do you do keep logging in and out or open mail in another browser application?
Actually, I have been using the new Thunderbird 3 beta which is better in many ways than Apple Mail, although I still use Apple Mail sometimes. Web mail seems to appeal to people who have little knowledge of mail programs (the masses) so this example would say that we are dummying up computer software for the masses and creating standards that are substandard in quality.
I've got GMail set up in Apple Mail, but honestly I rarely use Mail. It's a nice client, but the GMail web client is so good in terms of functionality that I just use that. Having used mail clients from Outlook to Thunderbird to Evolution and Mail, I do know my way around e-mail clients (more than I want to know actually, when it comes to Outlook

).
As for Chrome OS, I've been running it in Fusion for a couple days now, and well.....I don't see the point, at least not yet. While comparing it to Windows, OS X, or Linux at this point is silly because they've made the target very clear, it's in fact so limiting that even my Droid and iPT provide more elaborate "operating system" experiences.
The strength of the cloud, IMO, is not so much doing everything in it, but rather the backup and synchronization of apps utilizing it. For instance, DropBox and Evernote sync docs and notes from my work Mac to my personal Mac, to my DVR computer, and my iPT.
My wife wanted me to edit a photo for Christmas cards and then upload them to get printed, so she took the pic, dropped it in the Dropbox folder, I grabbed it at work, Shop'd it, then uploaded to MPix. Done. She saw the finished results in minutes, to give the okay (she's the boss, afterall

)