Three years ago, concert promoting giant Live Nation took over the historic Jackie Gleason Theater, celebrating the opening with a concert by Ricky Martin. Though there was some initial grumbling about the theater's corporate control — and its choice of a first act — most skepticism has fallen away. While the new Fillmore Miami Beach preserved the exterior of the old Gleason Theater, on the inside, it is a distant relative to the old venue. This new version is darker and sexier, a place where you might actually want to hang out rather than suffer through yet another production of The Nutcracker with Grandma. Where some acts would previously have been routed north to Broward County, they have been trickling into the Fillmore instead. In fact, just during the past six months, the venue's booking has really begun to cook, with names such as Wilco, Band of Horses, and the Arctic Monkeys all playing in a spectacular April.But the future of the Fillmore hangs in the balance. Miami Beach commissioners have agreed to hear a proposal that would raze the theater and turn it into yet another hotel. At the same time, Live Nation posted a loss again on the venue — and that might repeat next year. A grassroots campaign is underway on Facebook; search for the group Save the Fillmore at Jackie Gleason Theater. Music and culture fans of all stripes are banding together to sway Beach commissioners. If the hotel plan is approved, it would be a major blow to both historic preservationists and those with hopes for Miami's position as a music hub.