I answered this in one of the other Tormail threads. Gmail is a pain in the ass to use over Tor. You would most likely have to buy a burner phone to verify. I don't know about Hotmail/Outlook.com. However, Yahoo Mail is easy to register and use over Tor. They don't have good spam catching mechanisms, which is why spammers love to use them, but that's a feature for people who want an anon email account, too. Only problem with Yahoo Mail is it doesn't provide SSL support for viewing your email (only for registering/logging in), so the exit node can snoop on what you're reading. My suggestion is safe-mail.net, which provides SSL for everything on the site, and doesn't block Tor. You need to disable IP checking in the preferences, or it will log you out when you switch exit nodes after 10 minutes.