The Amazon EC2 is sooo slow. I spun up an instance for Amazon and Rackspace both to see how long it would take to render a frame in Blender. It is shocking how slow the difference was. I didn't do an apples-to-apples comparison, but the Rackspace blender 64bit 2.49b rendered in 47 seconds. The Amazon linux blender 2.48 rendered in 17 minutes!
http://www.jasonrowland.com/2010/09/amazon-vs-rackspace-for-...