Please Read - FORUM RULES!
Dynamic range is the area between the peak level (when the meter is up) and the low level (when the meter is down). Roughly, 3dbs to 6dbs of movement between the high and low meter level is a typical amount of dynamic range, but this does depend on the genre of music.
Note - One problem you want to watch out for (if you're mixing your own music) is dynamic range between song sections. You don't want a +10db or more difference between the verses and choruses. This creates a mastering problem because the verses will never be loud enough compared to the rest of the song. Roughly a 6db difference is as high as you want to go.