Favorite Wordpress Plugins?

WordFence Security plug-in is fantastic! 5 star rated.

A client's WordPress got hacked and I had to fix it.
They had an out of date theme that let the hackers in.
After reloading their site and cleaning/updating the mess...
I installed WordFence and it stopped an attack 5 minutes later!
It not only scans all files for changes but uses a known bad IP database.
If anyone attacks one of the 5 million sites using it, all get protected from that IP.

The only glitch I encountered was having to add one line to htaccess
If your server is running Litespeed you need to add "noabort" there.
It only stops the scanner from working, all else worked immediately.
Even then, it sent me an email telling me what to fix so it would work.
Very smart plug-in with excellent support.
Kudos.

 

Do you have experiences with social sharing plugins for Wordpress. I use Addthis , but it slows my website a lot. Can you recommend any other (faster) plugin?