You can sign in to Chrome OS using your existing Google account. If you purchase apps from the Chrome Web Store now and then get a Chrome OS computer next year, your apps will sync to the new laptop instantly.
Chrome OS laptops will all come with Web cams, and users will be asked to take a photo of themselves to use as their avatar. It's not clear if the Chrome OS avatar will override your current Google one.
If you're familiar with Chrome as a browser and smartphone-style apps, you ought to have a fairly gentle learning curve for Chrome OS. The apps are front and center, while tabs and controls are up at the top and in the corner.
Chrome OS also ships with a guest account option. This will open by default into Chrome trackless Incognito mode, saving both computer owner and computer borrower the hassle of clearing out unwanted data or programs.