As opposed to trusting Microsoft with your data?
At least with Google Gears I can keep a copy of my data locally on my Linux desktop and keep it sync'd with the cloud so I can access it with my Palm Pre or a web browser on a PC in a library.
Unless you are running your own mail server your email already exists in a remote location. The only thing "the cloud" does is keep your data on multiple, sync'd systems to eliminate downtime.
So you're already using the cloud, or at least an early version of it.
Trusting MS with my data? I don’t have any .doc, .xls, etc, nor proprietary data kept “in sync” with my desktop with anybody’s “cloud”. That’s stands about as much chance in hell as it would with tax companies wanting me to upload my tax data to their company for submission.
Sure, I keep BS email accounts out there but anything else, forget it.
My e-mails that matter are stored locally. Like all my data. The problem with clouds is the same problem dumb terminals have always had, one busted connection and all your computers are bricks until the main comes back up. Lose the internet, lose productivity. Using real computer when you lose the internet you tend to gain productivity (less screwing around at work).