Ink - I love it's fluidity. I've been taking a beginner art class. As a refresher really, but it has reintroduced me to a medium I left behind ages ago. I always found it too messy and imprecise, but lately I've been using it just for that reason. It flows so nicely, both from the pen and from the brush. The blacks are so true and the washes subtle. More to come with this I'm sure.