It may help some to know that ownCloud supports “external storage” connectors, which allow you to access, for example, your Dropbox account from your ownCloud installation.
This would allow you to reduce to a free-tier Dropbox account to use for those clients/peers/whoever that insist on sharing with you via Dropbox.
http://doc.owncloud.org/server/6.0/admin_manual/apps/files_external/index.html
