GIVE ANSWERS - العربية القياسية

Voĉdoni nun!RespondisLingva demando
Most Useful Dialect

I am learning Arabic on my own, and I know that there are a few dialects that are used just about anywhere. The book I have uses 3 different ones when it teaches vocabulary (Egyptian, Levantine and Formal/Written). Which one of these 3 is the more common or most useful of them?

 

Thanks!!