Make sure that guest users accessing private pages are redirected to the right place, your site's login page.
Easily manage user roles and capabilities from the WordPress dashboard in a GUI.
The only plugin I'd recommend for connecting your MailChimp account to WordPress
Add an upload form to the front-end of your site, and let users view a listing of files in any number of custom directories. Super customizable.
Supercharge the notification emails that WordPress sends out by customising them with HTML, inline CSS, and shortcodes and choose to send them to user roles or individual users.
Track the analytics of your RSS feed, and integrate with WordPress so you can redirect and customize your feeds automatically.
Use the Profile Builder plugin for WordPress to easily set up registration pages, login pages, and edit profile pages on your site's front-end with shortcodes.
A third party service which allows you to add customizable live support and chat to any WordPress site, and respond to questions on their dashboard.
Display a box at the bottom of posts and pages with information about the author of the post, pulled from the user profile, and a list of latest posts.