I have found Enigmail and Thunderbird to be easy and intuitive. Both are open source. Thunderbird is the email client and Enigmail is the plug-in.
Now try web of trust, key servers, revoking certs.
Then the finer points of what to when you find tons of different keys for people with the same name.
Then subkeys, short term keys, and keeping long term keys offline.
See.. easy!