The Russians just used a pencil...

Everyone knows the old Joke... the Americans spent millions of dollars developing a pen that would work in space, while the Russians just used a pencil.

Fisher, the company that developed the nitrogen pressurized ink cartridge, does make a pretty nice pen. The "Bullet" pen is iconic, and was on exhibit for years in the NY MOMA. There's the original "Astronaut" pen, as well as many interesting designs.

There's also the "Mars" pen, which is guaranteed not to run out of ink until man lands on Mars. Or the "Millennium" pen, which is guaranteed not to run out of ink for the rest of your life. They're somewhat pricey, though.

I always carry a pen with me. In college it was a basic blue BIC pen, because I was always lending and losing them. Lately it's been a 3-in-1 Dr. Grip, but I've worn out two, and now they're discontinued. I just bought a Fisher "Multi-Action" space pen. We'll see how that goes...