Whatever concerns anyone might have about the NSA, however you think they could have possibly spied on you (whether they bothered or not) your lack of security means there are a thousand other parties just like them, to whom you're just as vulnerable.
If you're worried about the NSA, and I'm not even saying that's dumb, then also worry about the Chinese, the Russians, the kid next door, and Nigerian spammers. Your plaintext is as equally visible to anyone who wants to read it. OTOH if you have your ducks in a row, then the NSA is totally confounded. That is, unless someone has already been waving that $5 wrench at you. But if that's the case, then you already know about it so the issue is moot.