This article in Wired provides the most compelling case to host your data yourself of anything I have ever read.
Here's what happened: Last week the FBI raided Core IP Networks, and seized all of their equipment.
The problem is that entire businesses were hosted on that equipment. A company called Liquid Motors has effectively been put out of business by this seizure. They sued the FBI for the return of their servers and lost. The excuse? Their servers "could" have been used in the crime.
They are one of about fifty companies that are collateral damage to the wrongdoings of another.
This is why I have serious reservations about having my data hosted somewhere else, no matter how secure they are. Core IP Networks provided duplicate servers, a hardened building, with multiple power sources and their own power generation. But all of that is irrelevant when the servers have been seized by the FBI. Based on past history you can count on several things:
(1) The FBI tends to be quite clueless when dealing with technology matters and
(2) They are in no hurry to get your data back to you.
If you host your data yourself there are still many dangers, and you still could be in trouble if you have a staff member using your servers for illicit activities (you check for that sort of thing, RIGHT?) but at least you are less likely to be collateral damage in someone else's FBI investigation.