Created for designers by ARTIS Software & The Iconfactory, xScope is a powerful set of tools that are ideal for measuring, aligning and inspecting on-screen graphics and layouts. Quickly available via the Mac OS X menu bar, xScope's flexible tools float above desktop windows and UI elements making measuring a breeze.

xScope is really seven tools in one that will help any designer do their job faster and produce more accurate result but it's not inexpensive at $26.95. It can however make Web projects a hell of a lot easier and so that you can spend more time creating and less time making things fit.