I apologize if this has been discussed before.
What about creating an email/Bitcoin client? It would be a straightforward email client like gmail or anything else, but with the addition of Bitcoin perks. For example, the ability to link email addresses with Bitcoin addresses would be a nice organizational too. I mean really...in how many instances is anonymity really going to be so important? It would be nice to be able to send an email to a friend/relative/businessman/etc. and click the "attach Bitcoin" button and send away.
Edit: Possible email conversations may include "thanks for the drugs!" and "damn, this really is the hottest pepper ever. My laptop and I are in the bathroom."
Yeah, there have been a couple threads, but it's a great idea. Using Bitcoin as a small postage would curtail spam.