While there are many excellent episodes (like the visit from The Green Hornet & Kato) of the Batman series that could be considered the 'BEST', we'll give the Batman movie from 1966 the honor. It includes four villians (although no Julie Newmar as Catwoman) and all kinds of exciting gadgets.
Batman The Movie
The Caped Crusaders take on four of Gotham's most notorious criminals at the same time. The Penguin, The Joker, Catwoman and The Riddler join forces to defeat Batman and Robin. Their plan is to take over the world with the aid of a secret device that instantly dehydrates people and turns them into dust. The film features an array of gadgets like the famous Batmobile, the Batcopter, the Batboat and the Batcycle. All of the POW, BANG & PUNCH you could ask for.
Batman - Adam West
Robin - Burt Ward
Joker - Cesar Romero
Penguin - Burgess Meredith
Catwoman - Lee Meriwether
Produced By - William Dozier
Directed By - Leslie H. Martinson
Written By - Lorenzo Semple, Jr.