whatever you do DONT dance 'la cumparsita', 'por una cabeza' or 'el choclo', they are sooooooo old (i mean performed too much!) get something original. all of them are seen a lot but some more than others. a good option if you want a cheerful music would be "dos canarios", if you want it dramatic pick "melancolico" or "encanto rojo", and if you want a song with lots of contrasts there's "Halcon negro".
you'll find any of them on youtube, just download the soundtrack.
