HALLELUJAH!  The long summer theatrical drought has ended at the Performing Arts Centre, with this joyous production of Singin' in the Rain based on the Gene Kelly-Stanley Donen movie musical splashing down this week for an extended season.  The MGM musical written by Comden and Green is regarded as one of the greatest musical films of the 20th century.     The stage musical, featuring Todd McKenney, Wayne Scott Kermond, Pia Morley (proving a genuine trouper when she had to stand in for injured Rachael Beck for the Brisbane opening), and Jackie Love, arrives as the happiest musical of the new century.     David Atkins and his team (including musical director Conrad Helfrich and associate director/choreographer Drew Anthony) have faithfully recreated the movie musical as a stand-alone stage show, complete with the movie's famous song and dance in the rain and the extended Broadway Melody Ballet, featuring McKenney and the vampish Michelle Hopper.     The wizardry Atkins showed with his contribution to the unforgettable Sydney Olympic Games ceremonies is again evident here.     While the production uses the original choreography created by Kelly and Donen, Atkins makes his own contribution with the energy-sapping number he's devised as a post-finale surprise that joyously caps off a thoroughly unforgettable experience.     The cast altogether are working with a lot more pep than in the show I saw in Melbourne last month.     The unfortunate injury to Ms Beck has given it the atmosphere of a first-run, as the show opened in Sydney last May, and had a Melbourne season before moving north.     McKenney's performance of the title number perfectly mirrors the classic Kelly routine, but letting McKenney's personality (glowing after his Boy from Oz triumph) shine through.     The romance between Don Lockwood (McKenney) and ingenue Kathy Selden (Morley, an attractive performer with a pleasing voice and easy dancing style) is believable, while Kermond (Cosmo Brown) and Love (the grating Lina Lamont) win over the audience with their antics.     Love demonstrates previously untapped comic potential, with split-second timing.     Jockey-sized Kermond shows his acrobatic flair with the Make 'Em Laugh number, and he and McKenney make an enviable team in the Moses Supposes number.     The story traces the evolution of talkies in Hollywood and the film clips which demonstrate the problems of adjusting to the new medium are hilariously recreated on stage.     Musical theatre enthusiasts will wish Singin' in the Rain could stay in Queensland forever, whatever the weather.