The temperaments: Click on images for details
12-Tone Equal Tempered Some temperaments are more equal than others!
Thidell Formula 1 Well temper, optimised for all standard open and barre chord patterns
Die Wohltemperirte Gitarre After J.S. Bach's "Well-Tempered Clavier"
If you are in search of something really different, see also: Meantone Blues