Watercolor... a color liberation.
An unlimited pallete. The greatest range of values. The tiniest detail, the widest washes.
Short of taking up acrylics or oils and moving from paper to canvas, watercolors allow the greatest freedom a traditional artist can hope for. And it's even travel-sized.
I use Van Gogh brand cake paints and Koi brand tube paints in my work.
For paper, I use Arches Hot Press 140lb Watercolor Paper almost exclusively. It is the perfect combination of very smooth texture with a heavy weight paper that comes in a block. However, when I use up my block of 20 pages, I plan on upgrading to 300lb Hot Press, which only comes in large sheets.