I have seen many attempts to improve that humble tool, the wire stripper. This is the one that pleases me most. It clamps the wire, makes an incision into the insulation without cutting the copper underneath, and removes the insulation, all in a single action. The best part is that you don't have to hold the wire, because the tool grips it for you. You can use it with only one hand.

It looks clunky and over-elaborate but is absolutely functional. I enjoy all aspects of its design, even including the snick-snick sound of its clever mechanical linkage.

Although the one I own bears Radio Shack's "Kronus" brand name (available on their web site and in their stores) an identical version is available more cheaply from Grizzly Tools at the URL below.

Kronus Automatic Wire Stripper
$10
Available from Amazon