Add any item in the tree to your Favorites (right click, select Navigation > Add to Favorites), including "My Computer" folders, playlists, view schemes, and purchases.
To view your Favorites, go to View > Navigation. They will appear at the top of the sub-menu.
To organize your Favorites, go to View > Navigation > Organize Favorites.
We recommend adding the "Navigation" toolbar button (right click on the toolbar space to customize the toolbar) if you use these often. Then you have quick access to your favorites.