I shrugged off Amazon EC2 a couple years or so ago when they made it available, after spending a couple days trying to play with it and see how it ticks. My reason for shrugging it off? If a virtual machine crashes, everything gets destroyed, all custom apps all data, everything. Best you can do is build a virtual machine that has everything preinstalled on it and then uses something like Amazon S3 to load and back up the data store. The problem with that is that it requires plumbing and engineering, as well as 100% planned downtime (no crashes or other unexpected reboots allowed, lest you lose everything since the last backup).

Now Amazon introduces this:

http://www.amazon.com/gp/browse.html/ref=pe_2170_10160930?node=689343011

With this, suddenly I'm interested again because now file storage persists in an EC2 instance when used in conjunction with EBS. I knew this day would come -- if not from Amazon then from Aptana's Cloud or from Microsoft's Mesh.