Mozilla Persona looks promising. I've tried implementing OpenID on an a private site, and it was a bitch to implement, and is really confusing to the few people who have tried to use it.
Persona doesn't look like it's that much easier to implement, but maybe I'm wrong. One step that looks particularly dubious is where the "identity provider" (owner of your email address) manages requests for certificates. That means that a lot of domanant email providers are going to have to come on-board. That might happen. But if you have your own domain name and you don't want an email address with one of these systems, it's probably not going to be a cakewalk to install the authentication step on your own server.
We'll see. I have hopes for this, but I'm not holding my breath!