Loop Master is a great tool for musicians learning tunes and licks. It allows you to select start and end points in a song and will loop between the two points. It is especially useful when used with a DSP plugin that can change the tempo and pitch such as Pacemaker.
You pick the beginning, you pick the end, loop and listen away. If you want to relisten to a certain section of a song, this plugin can come in very handy. You can even move the section you selected after it's selected. Guitar players enjoy.