If you are looking to replace your current stylus with something multi-functional, check out the YAFA 4.Palm. The 4.Palm stuffs a ball-point pen, a 0.5 mm pencil, an orange highlighter and a stylus into its ½" thick barrel (5/8" including the clip). It is translucent, and is available in green, blue, grey, orange and clear, colors that should particularly please readers with non-graphite-colored Visors and iMacs.
The secret to using the 4.Palm's different inserts is gravity. There are four icons at the top of the pen--a sun for the highlighter, a filled-in circle for the black ballpoint pen, an empty circle for the stylus and a written "0.5" for the pencil. In order to use a particular insert, just tilt the 4.Palm up about 30 degrees with the icon of the insert you want facing up, and push the button on the top of the pen. This deploys the correct insert and locks it into place. The release button is on the pen's clip. After a few hours of using it and getting used to the icons, remembering which is which should be no problem.
Of course, to fit all of the mechanics and inserts into one pen means that the end result is quite a bit larger than a normal pen or stylus. It does not fit in the stylus slot on the Visor, which is the first place I reach for when wanting to write something down. But if you can get used to reaching into your shirt pocket instead, you will enjoy the other functions of the 4.Palm. The stylus itself is black. I found that it does not stick out of the pen quite far enough for my style of writing. I tilt a stylus/pen a lot when I write, and sometimes the barrel of the pen drags on the screen of my Visor, which could possibly result in incorrect input. This problem will vary depending on the user. The black ballpoint pen writes fine, though it seems to be a fine-point pen, which does not work as well as a medium point with my chicken-scratch left-handed writing. The highlighter is basically an orange ballpoint pen insert. It works adequately for highlighting, but is excellent for editing documents because it is easy to write with and the color stands out very well. The pencil works like most mechanical pencils--very well. The button that selects the insert is used to lengthen then "lead." One of the more ingenious features of the 4.Palm is that there is an eraser hidden under the selector button. All inserts and the eraser can be refilled at the YAFA site.