If it's not too late and you're up for a group like SimonM suggested, I'd be up for joining in! My cell is 11-3850-0490, feel free to send me a text. (I may see that faster than something you post here.) I live in Palermo not far from Alto Palermo, so that theater would be easy for me to get to. (or wherever else!)
My personal favorite is Showcase, on Av. Monroe and Arrebenos in Belgrano.
I like it 'cause:
1) It's pretty easy to get to by bus or train (linea mitre, est. Belgrano), and they have most current movies showing.
2) It's close to "Chinatown" so a movie can be combined with a cheap chinese dinner.
My current favorite Peruvian restaurant "LaCumma" is only a few blocks away on Olazabel y Arrebenos, as well as "Lotus" (Thai) and "Hong Kong Style" (Montanesas y Juramento - Very good Dim Sum!)
Another pretty good parilla is "Pobre Luis", on Arrebenos just a block or two south of Showcase.