xScope: measurement tools for UI designers

This tip from Creative Bits:

If you ever design web sites xScope is a must have! It gives you
all the tools you need to take measurements on your screen in several different ways. You can have a semi transparent
cool looking pixel based resizeable ruler. You get a screen size mask, which is great to check how your layout work
in different screen sizes and browsers. The magnifying glass will help you check the tiny details. You can also have
guides, like in PS, but on all your screen. Resizeable boxes can help you make a rough layout while working in any
application. Finally the crosshair cursor will give you that nice übergeek feeling we all enjoy.

Measuring, aligning and inspecting on-screen graphics and layouts? 15 bucks. That nice ubergeek feeling?
Priceless.