They still have access to your data. This changes nothing, except maybe making changing the ISP a little easier.
Not if you encrypt it with your own key.
If you really want you can always host from your own colo box at a datacenter or in your own home.
Datacenter providers tend to care less about what you are doing (unless it's hurting their network).
Exactly.
I use ownCloud for dropbox-like sync and sharing (it's better than dropbox!), postfix + dovecot + roundcube for email, a Jabber server for IM, and am moving to Kolab for other groupware - Calendar, Tasks, RSS, Contacts, etc - encrypted on my linode instance. All connections are encrypted.
And it's a VM image, so I can always take it out of their system and use it elsewhere.
What is needed is a portable VM image that provides file sync, email and blogging straight out of the box.