"Do you have a preferred orquesta?"
I open most private lessons and practicas with this question and am usually greeted with a blank look, a non-committal shrug, or some variation of "Oh, I don't know, play whatever you like".
For a dance with an established canon of music, it's a shame that many dancers aren't more familiar with the music they dance to. Developing a familiarity with the most commonly danced music is a way to ensure more enjoyable dancing in the future. Not only will you be able to dance more musically with your newfound knowledge of the elements of each song, you'll begin to develop tastes and have better dances as a consequence. Maybe you don't particularly dance well to Canaro or maybe you don't like dancing with a specific partner to Di Sarli. Knowing the music will help you pick and choose tandas and the partners you dance them with to ensure you get the most enjoyment out of the experience. Dancing with someone who not only knows the music but consciously enjoys it is extraordinary, regardless of which role you dance.
How do you develop this familiarity? Listen, listen, listen. Take ten minutes out of your day and listen to a full tanda by one orquesta. Dance by yourself around the room to it or just sit and appreciate it. Listen for the differences from one orquesta to another, from one decade to another, from one vocalist to another.
I'm providing some jumping off points below:
Juan D'Arienzo has some very rhythmic arrangements and is a standard of many classes, practicas, and milongas for that reason. The variacion at the end of "Pensalo Bien" is particularly tricky and worth getting familiar with so it doesn't take you off guard.
Carlos Di Sarli tends towards the opposite end of the spectrum, with more lyrical arrangements that demand a different intention than the D'Arienzo tanda provided above. "Tus Labios Me Diran" is a personal favorite of mine.
This tanda of Anibal Troilo milongas has the added bonus of including the singer's name with each track.