Windows only: SecondShell adds a combination of shortcut key and mouse enhancements that make moving, resizing, minimising and closing applications simpler.
Once you've launched the no-installation-required utility, you can hold the Alt key down, and click-drag with the left mouse button to move windows around the screen or drag using the right mouse button to resize the window. You can also middle-click the titlebar to close the application, or right-click it to minimise to the taskbar.
There's also a number of added hotkeys, and you can customise all of the settings using the INI file in the same folder — since the utility is written in AutoHotkey, the syntax should be fairly easy to grasp for many Lifehacker readers. SecondShell is a free download for Windows only.