Tim was someone special. He relished playing villainous roles and did so often with a fun singing voice. Curry clearly enjoyed what he did and that's what made him so beloved for many years.
And as Icestorm mentioned, he was Dr. Frank N. Furter in "The Rocky Horror Picture Show", a movie I have watched twice and enjoyed but still have trouble dissecting. Beyond that, if you're down for a rewatch of his best live-action performances, be sure to include the sweet transvestite as well as Daniel "Rooster" Hannigan in "Annie", Wadsworth in "Clue", Darkness in "Legend", Pennywise on "It", Mr. Hector in "Home Alone 2: Lost in New York", Cardinal Richelieu in "The Three Musketeers", Long John Silver in "Muppet Treasure Island" and Billy Flynn aka The Prince of Darkness on "Criminal Minds". If you want to see Curry's best voice performances, I'd go with Captain Hook on "Peter Pan & the Pirates", Sir Gawain on "The Legend of Prince Valiant", Hexxus in "FernGully: The Last Rainforest", Gabriel Knight in the "Gabriel Knight" series, Mr. Leichliter on "Hey Arnold!", Lord Dragaunus on "Mighty Ducks: The Animated Series", Forte in "Beauty and the Beast: The Enchanted Christmas", Nigel Thornberry on "The Wild Thornberrys", Rex Pester in "The Rugrats Movie", Ben Ravencroft in "Scooby-Doo! and the Witch's Ghost", Mouse King in "Barbie in the Nutcracker", Professor Finbarr Calamitous on "The Adventures of Jimmy Neutron, Boy Genius", Prince in "Garfield: A Tail of Two Kitties", Chancellor Palpatine aka Darth Sidious on "Star Wars: The Clone Wars" and Auntie Whispers on "Over the Garden Wall".