Does anybody out there use Amazon EC2 to host their web sites and/or web applications? I'm intrigued by the concept, and am debating signing up, spending a few bucks, checking it out. No server to colo, yet you're not restricted with regard to what OS you can run and what apps you can run on it. So, I could have a custom Ubuntu box doing whatever I want -- hosting all my websites, running a bit of MySQL, etc. Is it worth the effort?