So, in an effort to hide from NSA you go all out HTTPS. However, to avoid getting those pesky "this site is dangerous!!!" messages browsers show you on self-signed certificates, you buy your keys from any of the larger certificate authorities. Safe? Sorry, no. Almost all those CAs work under American jurisdiction, or on delegation from American CAs. Assuming NSA doesn't get the keys in other ways, all they have to do to get them is to ask the CA and the company would have to hand them over.
With those private keys available they can listen in on the HTTPS conversations in real time, and there is no way for the participants of the conversation to know this.
Amusingly enough, the safest bid (well, to hide from NSA at least) would be to use self-signed keys despite all the browser warnings.
If you still want to get valid keys, here is an interesting discussion on which CA to choose.