Mehdi has two very powerful and free plugins that solve two specific problems that often appear when doing graphics.

The first one is called “Eraser Classic”. It basically turns a selectable colour into a transparent area, something that layouters/graphic designers need very often. Atleast I get alot of my sourcefiles with white or black background. Now you could use the magic wand or “select colour” to make it “go away”, but “Eraser Classic” does a much better job, first because it can select the neighbouring colours based on a “sphere” selection (rather than “cube” like the magic wand does) and secondly because it does smooth transparency.

The second one is called “Fine Threshold” which is a much better working substitute for the original “Threshold”-Function of Photoshop because it does antialiased edges. If you often scan handdrawn sketches to work with you will definately love this.

Get the plugins and try them out, both saved me alot of time in the past.