To me, the more interesting aspect of any of the clouds is the PaaS offerings. I like the idea of not knowing or caring what OS my stuff is running on or how many VMs back it. Throw some Node.js up into a cloud and have it run and scale automatically without me having to harden, patch, and maintain machines. Same with data - flip a switch and have a geo-redundant well managed database service as opposed to configuring and monitoring such a beast myself.

I like Azure Web Apps, Sql, and Storage PaaS offerings, as well as hosted Mongo and similar 3rd party services. In general, my experience is that they are cheaper and better managed than most stuff my customers roll themselves.

I would suggest that any "100% anything" shop look at the PaaS offerings of the various clouds and see if the benefits outweigh the risks.