Love it. I created a Windows Server 2008 R2 EC2 instance with ESBT, Visual Studio 2010, BizTalk Server 2010, and SQL Server then made an AMI from that. If I want a nice clean development environment then I simply log into the Amazon Web Services console and provision a new environment from that AMI all in under 2 minutes. This also allows me to maintain separate development environments for different clients and projects. There are a few gotchas but its worthwhile. Got to love the cloud. I have full access to my development environments from anywhere with an internet connection. Very fast start up and shutdown of projects too.