The admin bar is only visible from the dashboard. From the site's home page it's missing.
I disabled Jetpack again and reenabled it. Nothing.
I deactivated and reactivated notifications thinking that would help. Nothing.
I switched themes and it was still missing. I switched back to my theme, it's still missing.
If the problem remains when you deactivate plugins and switch themes, I wonder if it might cause by some cookie issues. Could you please try clearing out your cache and cookies?
http://en.support.wordpress.com/browser-issues/#clear-your-cache-and-cookies
When I did that, my Jetpack stopped working properly and hasn't returned.
Could you give me more details about this? What happens when you go to the Jetpack menu in your dashboard, and try to disconnect, then reconnect to WordPress.com? DO you receive a specific error message?