The final piece in the EC2 web-hosting puzzle has been announced:
This new feature provides reliable, persistent storage volumes, for use with Amazon EC2 instances. These volumes exist independently from any Amazon EC2 instances, and will behave like raw, unformatted hard drives or block devices, which may then be formatted and configured based on the needs of your application. The volumes will be significantly more durable than the local disks within an Amazon EC2 instance. Additionally, our persistent storage feature will enable you to automatically create snapshots of your volumes and back them up to Amazon S3 for even greater reliability.
Until now the only way to get real MySQL storage has been to jump through some hoops with multiple EC2 instances or back the database onto S3 (with subsequent latency overhead). With 100GB of outbound data transfer the smallest ECV2 image will cost you about $90/month for 1.7GB of memory and a dedicated CPU core. The price just cannot be beat.