WindowFlow is a window switcher that lists all your open application windows, even windows that are hidden, minimized or in another Space.
Moving through the list of windows you get a preview of each one, additionally a mini-desktop shows you the windows location on the desktop giving you a strong visual cue of where to start focusing your attention when switching.
WindowFlow is an alternative to Expose offering a more predictable interface and more powerful than command-tab; and it supports all the standard window control shortcuts to hide, minimize and close windows.
Using WindowFlow you can instantly move groups of windows between Spaces.