[Plugin: Improved User Experience] Email-only login (Facebook style)

I tried this plugin and the email login part works exactly as advertised on WP 3.4.1. This can be updated on the plugin information page.

I have one feature request that many siteadmins have been looking for a long time. It is not that complicated to implement, but no plugin exists for this yet. The desired feature is to allow websites to get rid of usernames completely in the registration and login field. It can be broken in these subfeatures:

1. Have only email field in registration (and set the complete email address as username for new users)
2. Have the registration field accept email login (and for those users created before the above feature was activated, also usernames)
3. Have the registration field say it accepts email and not mention anything about usernames
4. Add either or both the Full Name / Nickname fields for the registration screen and set either one to be the default display option instead of the username

This plugin already accomplishes item 2, and hopefully adding support for 1, 3 and 4 would be well within the means that item 2 required.

http://wordpress.org/extend/plugins/improved-user-experience/