People got scared when, in his iPhone 3G review, Walt Mossberg said that a Microsoft Exchange sync can wipe out your personal calendar and contacts (though not your personal e-mail). This is true, but it is only half the truth. What we have learned is that MobileMe—mind you, a paid subscription service—can serve up your personal data alongside your company's exchange data, so you don't have to worry about one knocking the other out when your iPhone wirelessly syncs. Bottom Line: If you can't or don't want to keep personal contacts and cal on your company's Exchange server, you can keep them separately on your Mac or PC, but only by paying for a MobileMe account. [MobileMe]
This really concerns me because of how invested in my Gmail account I am. My wife and I use the mail, calendar, notifications, and anything else that integrates with our iPhones. Why would I pay $99 per year ($150 for the both of us via Family Plan) for what I already get for free?