I think it's important for dancers to learn about orchestras as early as possible. So when I was recently asked to teach a musicality class at Barrio del Tango, as an addendum to the class I handed out a one page sheet with a list of 10 orchestras, 20 singers, and 40 example tangos. I also uploaded a youtube video with said 40 tangos and their lyrics synchronized, and made the pdf interactive with links to biographies of the orchestra leaders and singers, as well as to the songs.
Please feel free to use the pdf for your own students.
Below is a rough latex-to-html conversion of the text of the pdf (note: songs are not organized in tandas!):
10 orchestras, 20 singers, 40 tangos
You can listen to these orchestras and more at: www.ArgentineTangoRadio.com
The songs with synchronized lyrics can be listened at: http://youtu.be/SPOtTNb-0-E . This document, with embedded links to orchestra leaders, singers, and songs, can be accessed at: http://hps.elte.hu/~gyepi/10orchestras20singers40tangos.pdf