Really, the cloud concept is nothing new, it's just a mainframe/thin client concept. The problem is that it requires a lot of different components to work together and it's still in its infancy.
To host a server (file, exchange, etc.) locally is not a big deal. It is well understood, you have complete control over the environment and you receive alerts if the application, server or environment has any problems. All equipment is a just a few feet away in a secure location, connected via LAN. If we lose our Internet connection, we can all still work at the site.
To use the cloud, I have lost a lot of control and I'm dependent on several major factors outside of my control. Any one loss prevents me from working. You need a solid Internet connection (or really redundant connections). You need the cloud provider to do everything else in a timely manner. If a business is down, they lose money, so the 'sorry and here's a credit for another day' doesn't really cut it.
Someday as the technology, security, quality, monitoring, management services improve (or get close to what is already provided onsite today) then we can look into cloud services.
I won't have anything to do with it. The cloud is just 'puff' and will pass as a failed attempt to increase revenue for the greedy.
Cloud services are a compromise solution at best. If you are OK with the compromises, go for it; if you aren't aware of the compromises, you haven't done your homework.
I am one of those server huggers I have heard about. I don't want the cloud to take my job and expertise from individual companies. Shoo. Go away!!