Extend the Dock and get window previews whenever you hover your mouse over an app.
DockView is a desktop customization app that lets you take a neat trick from Windows and mimic it in Snow Leopard: with DockView running, when you mouse over an app's icon in the Dock, you can instantly see live thumbnail images for all the windows open in that app.
Window management to divvy up your screen into exact portions.
Hover over the Dock for window previews and enables window snap.
Move, fullscreen, and pin windows using the green zoom button.