Shashank Sahu

Easy Login and Registration features with popup.
Features:
<ol>
<li>Easy to Login and Register (as modal)</li>
<li>Well customizable</li>
<li>100% responsive</li>
<li>provides sample login and registration pages</li>
<li>Compatible with all themes</li>
<li>Tested with latest WP version</li>
<li>Possible to replace wp-login.php with a custom “Login”, and “Registration” pages</li>
<li>provides after-login/registration/logout actions</li>
</ol>
Customization options:
<ol>
<li>Add plugin’s classes to your buttons to attach modal.</li>
<li>Select pages for ‘After-Login actions’ and ‘After-Logout actions’.</li>
</ol>

Wonder Login

Easy to implement login and registration by ajax .

shawfactor

This plugin allows you to turn of or shutdown registration via Buddypress, without effecting other functionality.
I built this as I don’t like the way Buddypress does registrations but liked most of the rest, but you could use it if your site was full or invitation only for instance.

LH Disable BP Registration

Shuts down registration via the usual Buddypress method, all other functionality is not effected.

Wonder Login vs LH Disable BP Registration