Handy Zoom

Summary:  Hold Option + Space then hold the Left Mouse Button and drag to zoom in/out of the timeline or composition window (whether the panel is active or not).

Description:  (Exactly like in Photoshop) Hold down Option + Space to allow zooming, then hold down LMB and drag in/out to zoom in/out. In the composition window the view scales smoothly, not by 20% increments, and when in the timeline the view zooms in to frame level or zooms out to view the entire composition.