I've been somewhat happy with the Pilot G-2 07* gell - when I can't find a Uniball Signo*.
*Manufacturers interested in my online and public support of their writing products should send a case -100 count or more- of a medium point, black ink, to the following address...
Haha
I do like the Pilot G2 chambered in 0.7 mm, but gel ink is too dark and smudge-prone for my taste, plus the relatively large volume of ink discharged during normal use causes the line to broaden noticeably, not to mention the cartridges run out of ink prohibitively fast. So while the Pilot G2 may be my favorite pen to sign my name with, I prefer the Zebra F-402 which, while also possessing a tasteful 0.7 mm point, produces a fine yet powerful line, one that is neither too dark like the G2's nor crudely light and inconsistent like so many cheap dime-a-dozen Bics.
On top of that, it's sturdy and has a stainless steel barrel; it's got weight, and it's got authority, and for enthusiasts of torquing your pen into the air and catching it as you think about what to write next (such as myself) it has a mass distribution I've not encountered with any other pen to date, granting it a sensible center of gravity that allows measurable throws and accurate catches.
For the price, it's the best pen you can buy.