keeping possession of a private key secret

[Anonymous Sender]

If I create a keypair in the normal way, the mails, files, etc.,
encrypted with it are protected by the passphrase as well as the
private key.

But access to my hard drive would easily reveal
$ gpg --list-secret-keys
my secret identity that I want to use for pseudonymous publishing.

Any suggestions on good ways to keep it secure without too much hassle
every time I want to use it?

Thanks.