It depends on your situation. If you are a learning for social dancing. It would be good to find out what others are starting with and what is played a lot, at were you plan to go dancing.
One of the keys to learning in social dance, is getting opportunities to get on the floor and dance. We go dancing in three different areas and the dances people start with are slightly different in each area. Waltz and chacha are the 2 dances people start with in all three areas we go to. Each area has a different third dance. In one it is salsa, single time swing/hustle in another and east coast swing in the third.
Waltz is harder to master than the others, but it does seem to be a popular dance to start with in our area.