Two big things in the news today, both are excellent examples of why you want to go ahead and ‘own’ your own email.
The first event was Microsoft breaking into a Hotmail account of a blogger/journalist to find the source of a leak. While it was stupid of these people to use a Hotmail account in the first place (and the guy was on the wrong side of the law), this shows Microsoft’s true character — they don’t care about your privacy. Just a terrible move, and I hope they get punished for it, both legally and civilly.
If your email contains or ever will ever contain sensitive information, you shouldn’t be using a free webmail service whose entire business model relies on analyzing your mail’s content for advertising purposes.
The second event is Google mining student email to figure out how to better target ads and such. This is sadly par for the course with Google. (I personally don’t even like emailing people who use Gmail.)
So, unless you are totally fine with your email being accessible to the government, and the company hosting it, I suggest you go host it yourself.