PGP is a widely accepted and used form of public key cryptograpy. Sadly, it is no longer free unless you go with the feature-poor GnuPGP.
Public key encryption is never going to catch on in the main stream. It requires both users to not only download the cryptosystem, it also requires that they both either send each other their public keys or that they search for the other's key in a public certificate authority.
PGP is secure, you can form your own key pairs up to 4098b, which is well above current commercially available key-lengths.
Which for most people means total security.
Just remember, encryption isn't about making data secure forever, it's only about buying time. With 4098b, you've got a lot of time on your hands.