If '30s elegance and big band, jazz, and upbeat dance music are what you're into, it's hard to beat the Starlight Room, high atop the Sir Francis Drake Hotel above Union Square. Elegance is key here, from the walnut-paneled elevators that whisk you up to the hotel's 21st floor, to the silk-draped chandeliers and burgundy velvet booths. And since the dance floor (which sports an old-fashioned mirror-glass glitter ball in the middle) is windowed on three sides, the city lights views are to die for. There's a live orchestra on Friday and Saturday nights, with DJs other nights. Entertainment starts at 8:30 p.m. And guys, don't forget the dinner jacket. Dress code is strictly enforced.