Because St. Louis has so many old buildings, it is no surprise that there are a lot of cool classic movie theaters including the Tivoli and the High Pointe. I went to the Moolah, located in Grand Center near SLU. Tickets a incredibly cheap ($6 to see The Hobbit on opening weekend). The building used to be a Masonic temple, so the interior is somewhat strange for a movie theater. On the bottom level there are really comfy couches which are perfect for a date. On the top level, there are uncomfortable looking chairs. Moral of the story is to get there early.
My one concern with the building is that the upper floors are a SLU dorm. During my movie (luckily during a boring dialogue scene) the fire alarm went off because the students messed up cooking dinner. They were able to pause the movie, but the fire alarm wrecked the mood of the movie and it took me awhile for everyone to get back into their seats.