Pens I use, in no particular order ---
-- Pilot Razor Point (black ink) and a Niji Waterbrush (or a brush and a cup of clear water) for pen+ink+wash sketching - These ubiquitous cheapie pens are loaded with a very nice water-soluble ink that washes easily to a nice deep blue-black. (See two examples here: http://www.wetcanvas.com/forums/showthread.php?t=418470
Once you moisten the line and let it dry, it becomes a mostly permanent mark and you can watercolor with abandon. Pen available at any office supply store (be sure to get the silver pen with the black ink), any art supply store, or from Dick Blick for less than two dollars, here: http://www.dickblick.com/zz207/03/
-- Copic Multiliner -- When I want a solid waterproof line. Copic pens are refillable come in six widths, at $2.50 each. Alternative is the Zig Millennium at $1.89 each or the Sakura Pigma Micron Pen, at $1.84. All three of these are available at any local art store or from Cheap Joe’s or Dick Blick online.
-- Lamy Vista fountain pen with a 1.1 mm calligraphy nib -- My sketchbooks are really sketchbook/journals and I like to write as well as sketch, so I have been using this fountain pens to do both. The black ink that comes in the cartridges is okay but not as good as some of the beautiful water-soluble inks out there in bottles. If you decide to go that route, be sure to buy the converter, so you can fill from bottles. These pens are available from John Neal, for $35.00 plus $4.95 for the converter: http://www.johnnealbooks.com/prod_detail_list/7
You can get the same 1.1 mm calligraphy nib on a Lamy Joy body for a tiny bit less money. But it is a longer pen. Not very compact. Again, be sure to also get the converter.
-- Niji Waterbrush Mini Set (12mm brush point) filled with black ink. Use three and fill each with a different dilution of the same ink so, together with the blank clean white of the paper, you have four tones to work with. The waterbrush is $5.58 at Dick Blick: http://www.dickblick.com/zz051/33/
-- Pelican M200 with a medium "I" (italic) nib, filled with any of those fun inks listed below. Outstanding writing AND sketching pen, very fluid and smooth. The pen is available at any good pen store or online for around $80.
INKS!!! Water soluble inks that I have found so far that I like:
- Private Reserve Velvet Black - jet black lines that wash into a beautiful black with just the tiniest hint of plum. Beautiful!
- Noodler’s Walnut - dark, dark, brown lines that wash into a perfect burnt sienna color. Gotta work fast before it totally dries.
- Private Reserve Chocolat - very dark brown lines that wash into a reddish burnt sienna color. (Example is here
I do not do stipples and so have no use for the "technical" drawing pens that I used way back when, when I was in grad school. Those Rapidiographs. Aaack. The name alone makes me shudder with the memory of the maintenance required to keep them from totally and irretrievably seizing up when left open for more than a half an hour. I don't draw on drafting film any more! If I want to use those archival waterproof PH-balanced no-fade will-last-longer-than-the paper inks, I will use the Copics and their cousins, or ye olde Speedball dip nib with Noodler's Bulletproof Black ink.