I think if you're really concerned about the Feds snooping on email, you need to use end-to-end encryption. Any large ISP or portal is going to be a juicy target, and since the majority of people don't want to run their own email servers, the only recourse is not to depend on trusting the servers. Even if you managed to convince everyone to leave G-Mail, they'd still congeal back into another 2-3 big services that the NSA can target.