That sounds like a fun idea for an app/service. You provide it with your base email address or custom domain and it generates a couple random words and keeps track of what service you used it to sign up for.
As long as you use a secure password, and you don't use the same one. I don't see alot of difference, but the ability to sandbox each service to a list of email accounts, so that the attacker never knows the master account, would be an extra layer of security.
Utility exists here. I just don't think there's enough utility to justify the work.
End result is that everyone gets a unique email that can't be guessed, I can nuke an address as soon as it starts sending me spam (often) and my true inbox is typically completely clean.
I initially made the mistake of trusting my bank and utility billing systems with my real address. Turns out my power company had their database compromised, and when I called to inform them they refused to believe me (like Dropbox).