I've been using the Cloud as hosted by Amazon EC2. Unexpected value? Yes... as a staging and test deployment platform. The value comes from the ability to take a more deliberate path that puts off hardware purchase plans. Being able to feel like you can really think out the deployment is quite a luxury.
Right now I'm enjoying thinking of using the cloud as a type of DMZ... at least until it's production time. But who knows if I'll want to just keep it in that role through production deployment?
I also like it for the potential of having standardized test platform images. These are pre-configured operating environments that you clone out based on the environment that you've set up and refined. Beats starting over every time you want to create a 2nd, 3rd or 4th testing environment. The only downside to images that I've come up with is this: You often want to assign new developers the task of setting up these environments from relative scratch so that they get an deeper impression of what goes in to setting up the server applications that they've been hired to build, expand and maintain. Without that experience, months and years go by before they really realize how the application they work with is choreographed with respect to support bash scripts, file system layout, including the use of NFS, and other supporting processing, such as a messaging server. There are also the critical configuration property files they read from.
So, what do I think of cloud computing right now? Very cool. It's taught me a lot about firewall configuration, in particular. It's made me feel empowered to try stuff without being dependent on IT. And it simply gives me another arrow in my quiver when contemplating test and, maybe, production deployments. Now... I've got to figure out the contrasting values of going with a hosted cloud versus an in-house VMWare-style cloud... hmmm...