I EDC a Zebra 701, its not small like the compact 301, but its built like a tank. I bet an industrious guy could cut one down to take the compact refills .... that would be cool.
I like my Pilot G-2 Mini ...but its 100% plastic..so easily broken, even though mine isn't, it still concerns me. Not an issue with the F-701.
As for the Space Pen crowd ...I too have several pens that take Space Pen cartridges and have bought new refills thinking I got a bad one every time it globbed ink onto the paper until I finally gave up. I over it. Zebra pens work fin ...they are not very pricey and I can run the cartridges dry satisfying my desire to use it up before trashing it.

To each his own, but I personally loathe the whole Zebra crowd (I mean the refillable ballpoints). They blot, they skip, they're expensive, they're overrated. But they do look pretty. I just tossed out the whole lot, banished forever from my office, and don't let the door hit you on the way out.

I wonder if it has to do with altitude. I live at 5300 feet.

[edit - Wait... Fischer markets these things as "astronaut" space pens. And if astronauts are actually using these pens at their altitude, they'd be having to deal with ink globs the size of bowling balls. So maybe it's something else besides altitude. ]

I'll chime in with those recommending the fisher bullet pen. I've carried one for years and like it very much:
Compact
Metal construction
Writes smoothly
Fits well in my hand with the cap on the back.

rite in the rain tactical. Used the space pen refills

I have a couple options. For the cheapest route, you can simply cut down an existing disposable pen. Here is an instructable describing the process: Mini BIC Keychain Pen! I did something similar with a click pen to make it more compact to so I could carry it in my Scout uniform pocket (the pockets no longer fit a standard sized pen).

However, since doing that little project, I've started carrying an Inka pen as a part of my EDC. I really like this pen, it has a pressurized ink cartridge like the Fisher space pens (and, according to what I've read, can use the Fisher universal refills or the Inka ones), and can be used quickly as a small pen or, with a little more effort, a full pen.

Here are the 2 pens (the Fenix E01 provides some scale), the Inka is shown the way it is when its not in use:



For quick uses, the Inka just pulls out and the metal cylinder remains attached to the keyring. This is good for when you just need to jot something down quickly. For example, I've recently started geocacheing so this what I'd do when I need to use it to write in the log after finding a cache.



Finally, if you are going to use it for more than just a quick note, you can assemble it into a full-on pen. The metal cylinder unscrews from the key chain and becomes the top half of the pen:



I've had this for a few months now and its proved pretty useful; I'm happy I decided to make this a part of my EDC.

I also noticed there is now a newer model available, called the Inka Mobile Pen + Stylus, and it looks like up here MEC has started carrying as well as the Inka I have. It looks like that one is always only a stubby pen though which makes it less attractive to me.

The Inka model I have goes for $18 up here and that newer model is $14.

It seems to be in the design of the Bullet pen. I've had one that did it repeatedly. I've also had their matte black pen and IIRC didn't have that problem. My current EDC is the Tao Pen from CRKT that uses Fischer refills. It isn't doing it at this time (over a year old).

I've EDC'd an Inka Pen for about 5 years. No globs, ever. Converts into a perforating device in extreme situations.

http://www.kaboodle.com/reviews/inka-pen-travel-pen-1

I am a huge fan of the Fisher Space Pen

Trekker