So, the NSA can read my gmail. It will probably put them to sleep. I am not concerned about putting NSA agents to sleep.
Perhaps they might find out I buy stuff from newegg form time to time? or about my average bills? Sure, I could spend a lot of time (that I don't have) and effort to setup my own computer running my own SMTP server, and have to setup my own SPAM filter and maintain that, using copious amounts of time that I don't have.
Perhaps I could even use PGP to encrypt both of the personal e-mails that I have time for per year, but what would I really be accomplishing? To claim that I am being "private" and "secure".
Also, even the NSA does not have the resources to read each and every one of the 294 billion e-mails sent every day. The best they can do is to quickly scan a small percentage of them. most likely for a fairly narrow target criteria.
No thanks, I'll continue using my gmail account that filters the spam for me. Especially since 90% of the e-mail that make it past the spam filter is utility bills and the like. I am not interested in hiding the fact that I heat my house with gas from the NSA...