Well, I use an old, reliable Wacom Cintiq 21UX (which is no longer being produced) to do most of my art, and it is a wonderful piece of equipment.
But if we're talking traditional art, my favourite tools are this:
a.k.a the Pilot Pocket Brush Pen Soft, which is a dream to ink with. It's got all the flexibility of a brush, and all the control of a pen. The line-width variation is wonderful. <3
When colouring traditionally, I mostly use Windsor&Newton watercolours.