I'm looking at the list of licenses and wondering if there is one specific license that enables personalization. If so, which license should I be looking for?
Using Sitecore.NET 8.0 (rev. 151127)
You should have Sitecore.xDB.base license.
Sitecore 8.1 now requires a license with the “Sitecore.xDB.base” key to enable all features of the Experience Platform. If your license file does not contain this key, Sitecore will default to Experience Management (CMS-only) mode. Any customers or partners with a license to Experience Platform should contact their account manager or login to SPN if they are missing this key.