The regular major scale is Tool Nr 1! Not only is it the basis of almost all melody, you'll find out that the knowing and using the major scale well, you can sound pretty cool and jazzy, if you know how to use it. Mastering the major scale is a big step towards jazz improvisation; in fact, if you can't play the scale fluently, you can't improvise fluently; it is a necessary skill.
Along the way some cool chords are introduced, to get you started with playing the scale over some chords. By practicing the scale over some chords, you not only learn the scale , but you get a feel of how it sounds in a musical context.