A UI customization setup for the Razer Naga 12-button mouse.
Three 3x4 quickbars. Shift for the left side, nothing for the middle and Ctrl for the right. Personally, I like having abilities for my most common rotations in the middle default quickbar, secondary attacks and offensive buffs/CCs on the left, and defensive buffs/escapes/medpacs on the right.
Updated 4/16/12: Added two more 3x4 quickbars to use with the Naga. Shift for the left side and Ctrl for the right.