I've a few to add.
1. Privacy Policy: it's needed if using Adsense and this is the fastest way of getting a quick one up
Privacy Policy Plugin For WordPress
2. Homepage Excerpts: helps to stop duplicate content on the homepage/post pages
Homepage Excerpts Wordpress Plugin
3. WP-db-Backup
Il Filosofo WordPress Database Backup
4. Wordpress Automatic Upgrade: can upgrade to the latest build of WP with a few mouse clicks.
WordPress › Wordpress Automatic upgrade WordPress Plugins
Plus, I use the majority of what Glowleaf mentioned too.