I've been working on removing myself from the Google silo for the past few months. It's tough, and the alternatives just aren't as good or convenient as what Google offers, but I think it's an important thing to do at least on principle.
I found Owncloud to be difficult to install and very buggy. For self-hosted CalDAV/CardDAV, I chose Baikal (http://http://baikal-server.com/) instead of Radicale. It seemed easier to set up and it's been working great so far. There's no web interface unfortunately, and the Thunderbird addon that connects to CardDAV (SOGO connector) is buggy at times too.
Replacing Dropbox doesn't seem practical right now. Owncloud is buggy, Sparkleshare seems like a "when you've got a hammer, everything's a nail" kind of solution, and I haven't tried Seafile yet because the configuration is intimidating and I haven't really heard anything about it.
Rackspace has great hosted email for $1/inbox/month. Eventually I want to bite the bullet and host my own mail server (I still have nightmares from when I self-hosted email a few years ago) but in the meantime I've really liked Rackspace.
Hacker idea: Create an OSS self-hosted email appliance. Simple setup for a one-inbox self-hosted email server, including DNS, DKIM, spam filter, etc. No matter what anyone says Dovecot/Postfix is not for mere mortals and self-hosted email in general is so full of pitfalls it could be an Indiana Jones temple.