Sketchbooks: Of late have been playing with Moleskins. I prefer the watercolor paper in those.
WC Kit: I've been using a little Winsor Newton Cotman kit and like it's many mixing wells. Though it's a little bulky. Also needed to velcro the water bottle in to keep it from falling out in transit. Will replace the pans with good paints soon.
Case: I love my little pencil/pen case. I got it from jetpens.com. It packs tons of stuff. Plus there's still space! I'll probably make some modifications to it so stuff doesn't fall out on location. A problem I've been having. I'll add a flap to the top edge.
Pencils: Regular 4Bs are dandy. Black Prisma color I use most. Sometimes china markers. Also Stabillos, which are water soluble.
Pens: I'm an ink pen nut and have been using fountains. Would prefer to carry ink and croquil type nibs, but leaking bottles are an issue. I'm hunting for leak proof so I can indulge. I've been using a Lamy Safari, which I like. It has a fine nib which is a little fine for most of my drawing. I like a beefy line and draw large, which makes the fine line even finer. It's a wonderful pen though. Great for writing. Very smooth.
Inks: Noodlers has a great selection of colors. I like to mix my own.
Brush Pens: I lOVE my brush pens. Kuretake #8 is my favorite so far. It's a fountain pen, so you can load it with any ink color. It's inexpensive too. Has great sensitivity. I'm also experimenting with the standard Pentels. I like those too. Can get a super thick, bold line with them.
Waterbrushes: are brushes that you fill with water. You just squeeze a little to bring the water to the tip. Eliminates the need to carry water when you're on location. I have a Niji large, Kuretake large (exactly the same) and a Kuretake Flat. It has a cap that makes it a flat that you can remove and it becomes a large round. Two brushes in one. The water brushes allow for some interesting wash effects. They take some getting used to, but are worth the effort.
Brushes: I carry a few sables. Small and medium both in rounds and flats.
Copic Pens: Are felt tip nib type pens. Not a very expressive line, but I like them.
Where to Purchase: The pens and water brushes can be purchased at jetpens.com. $25 bucks gets you free shipping. W&N Cotman kit can be purchased at Jerrysartoramma.com or Amazon. Shop for cheap on this. $19.99 is the lowest I've seen it. Get Moleskins at Amazon.
Now go have fun!