My own favorite, the Pilot Precise (pictured above) comes in joint second place.
Of course, there's rarely any reason not to just use a pencil.
I've carried a Fisher Space Pen Bullet on and off since I was a kid. ("Write underwater and upside down!") I usually lose them in a matter of weeks, but while I can manage to hold on to one I do appreciate its minimalist design, small size, and great "fiddleability." Of course, the Space Pen is surrounded by some epic marketing and myth. Did NASA really invest millions to develop a perfect pen for astronauts? No, apparently, Fisher had developed the pen technology and later brought it to NASA. Following two years of testing, the space agency bought 400 of the pens at a 40 percent discount. And on October 11, 1968, Apollo 7 astronauts carried Fisher Space Pens, model AG7, into orbit.
Fisher Space Pen AG7 (Amazon)
Wacom's Inkling is a pen that draws both on paper and on-screen, tracking the artist's linework with 1024 levels of sensitivity. At $200, it's barely even expensive! The Inkling will be in stores by mid-September.
What the crap is a tactical pen? A pen that kicks ass, basically. And I don't just mean it's "a kick-ass pen," I mean: this pen could literally kick your ass. To death, maybe. But it's also a pen, so it's civilized. No definitive answer on how mighty a tactical pen is in comparison to a sword, but the tactical pen is definitely mightier than the regular pen.
After first hearing about these on Every Day Carry, I decided I needed to see one in person. So I picked one up. Then another. Then did some comparing and contrasting, all scientifical-like. I can now share my results with you. Here's a few that happen to be in front of me as I write this post.
From L to R: Smith & Wesson Tactical Pen, Emergency Survival Covert Spy Ventilator Pen (carbon fiber), County Comm Embassy Elite Pen (stainless), Pilot Easy Touch (fine point), Sharpie (standard).