The idea of cloud computing has merit, in that you can store your data on multiple storage facilities in secure data centers and limit your own responsibility (and liability) by not having to purchase/maintain the systems yourself. However, and this is the big deal with cloud computing... you don't own the infrastructure. Someone else does and this can cause a huge problem down the line when your data gets locked up or lost. If you are a decent sized corporation with some money and lawyers, you can fight the cloud vendor and protect yourself to some extent. It would be unwise for the individual to use cloud computing for anything more than email because individuals have less rights than a business who has lawyers to sue and fight for them if their data is lost "in the cloud".
So, aside from the technical possibilities such as using fiber, IPSec, MPLS, or some other media/protocols to improve performance/security of data transmission to/from the cloud to your organization, the serious concerns of availability come into play. No company who would take cloud computing or IaaS as a business will take all liability. Caveat emptor is still in play. I am personally not ready to store my important data "in the cloud". Businesses may be able to get away with it if they have good lawyers.
