I ask this question somewhat in parody of the threads about fountain pens, but there is certainly a legitimate use for ball-points when one cannot always have a fine pen on hand. I am a fan of the Pilot Precise Rolling Ball V-5 in purple. The V-5 is what Pilot terms an Extra Fine point. The Precise is also available in the V-7, a Fine point. I naturally write in fairly small print so I much prefer the thinness provided by the V-5. The shape of the pen is slender, the weight light but not insubstantial. Contrast this with its primary competitor, the Sanford Uni-ball Vision, which I feel is needlessly fat. I also find the Precise easier to twirl though of course this varies with one's twirling style. Perhaps the only clear advantage of the Vision is its more durable cap -- the Precise's is prone to cracking. The purple color is very unique, allowing me to easily distinguish my writing from that of others from even a distance, while still being legible (as opposed to say, pink) and easily photocopied.