You're right about 0.5 and 0.7 being less than ideal, but lead holders have their own drawbacks, such as a generally unclutched propelling mechanism (i.e. one i

You're right about 0.5 and 0.7 being less than ideal, but lead holders have their own drawbacks, such as a generally unclutched propelling mechanism (i.e. one incautious nudge of the advance button and your lead's on the floor in ten pieces), the need for a sharpener, and the lack of an integral eraser -- that latter concern being of especial import in the search for a writing implement suitable for daily wear. That's why I use a Pentel Twist-Erase III in 0.9mm. It offers a lead thick enough to be reliable without requiring manual resharpening, and the feature for which it's named is the 1 x 1/4-inch cylindrical twist-advance eraser on the other end -- easily equal to almost any rubbing-out task, and composed of some no doubt space-age polymer which stands up admirably to the harshest frictions. And, quite aside from the excellent functional design of the tool, its aesthetic qualities are matchless -- between the gloss black body finish and the chrome accents of ferrule and pocket-clip, this pencil captures a timeless elegance of style which is right at home in any company. Plus, they're five bucks a pop and they last forever. What's not to like?