I tend to leave too many pens inked up at one time. But I am always hoping to be able to use each and every one of them at a moment's notice. Currently, I fear I have nearly 30 pens with ink in them. It is nearly impossible to keep that many flowing well when you are working as many hours as I am now. So, periodically I find myself up until midnight cleaning, purging and refilling several pens in an effort to keep them all flowing smoothly. The more different colors of ink that I get, the more that I want to have each pen able to offer a different color of ink. Trust me - I don't have thirty bottles of ink.
Recently, I have gotten some new bottles of ink which are fantastic: One is Noodler's Black Anti-Feather. It always provides a perfect line, doesn't skip and will stay flowing even after being left for several days. And it writes extremely well on the seemingly ink resistant Moleskin paper. It won't even feather on cheap copy paper - amazing!
The second is Noodler's Burma Road Brown, which is a wonderfully rich dark brown ink. It also wites well on Moleskin paper. It doesn't feather much either.
Third is J Herbin - Gris Nuage (Grey). This is an interstingly strange ink. When it first hits the paper, it is a very dissatisfying watery black. It looks like black ink does after you have just rinsed your pen and there is still some water on the nib. But once it dries, it becomes a distinctly flat battleship grey. It is remarkable. This ink is a lot of fun to doodle with, particulalry if you combine it with black and use the grey as a sort of highlight, or as medium shadows in a sketch. I haven't used it much yet, but so far I had no feathering, skipping or drying problems. This ink also works well on Moleskin paper.
While it may appear here as though all inks work well on Moleskin, the three inks listed here are the only ones that I have that work very well on Moleskin paper. Waterman Blue/Black works fairly well on Moleskin. Other inks that are adequate on Moleskin are Levenger Cobalt Blue and Levenger Blue Bahama.