Wanted: Most secure unencrypted email solution

Dear lazy web,

Thanks to the global surveillance disclosures, I am searching for a secure email solution. Using end-to-end encryption seems to be the only secure solution to keep the email content private, but it does not protect your email header. End-to-end encryption has the big drawback that the communication partner has to use it, which is rarely the case. I want to communicate as secure as possible even with people that do not use end-to-end encryption. What is the most secure unencrypted email solution?

Should I rent a (virtual) server in my country (Germany) and run my own email server on it? Do you know any reliable, inexpensive server host for such use case?

Email usage statistic

A good week ago I tested Mozilla Thunderbird using IMAP. I created a statistic after seeing the mass of emails.

Emails received send received / day send / day
last week 902 334 128,86 47,71
last month 3728 589 120,26 19
last year 19377 1833 53,09 5,02
previous year 3070 434 8,41 1,19

The number of daily emails is continuously increasing. The last week was a peak of course. The average is probably something between the values of last year and last month. The increased email usage has various reason. One big reason is the increased involvement in the free software community. For example my GNOME-Colors directory contains 881 mails.

How many emails do you receive/send in a day?