Gusta or Gustan?

With gustar the verb agrees with the thing that is liked, not with the person who likes it.

• One thing → gusta: Me gusta el té (I like tea)
• An activity (infinitive) → gusta: Nos gusta nadar (We like swimming)
• Several things → gustan: Me gustan los gatos (I like cats)

The person does not change the verb: A los niños les gusta el helado (The children like ice cream) – many children, but one ice cream, so gusta. Two infinitives together still take gusta: Me gusta leer y escribir (I like reading and writing).

Encantar (to love, to really like) follows the same rule: encanta / encantan. It is already strong, so it usually goes without mucho.