Big pens are enjoying wide popularity, the bigger the pen the higher the price. The nib should be very big in relation to the body and broader writing nibs are more in demand than the extra fine sort. People want to make a bold statement with the look of the instrument and the line it puts down.
A pen’s filling mechanism affects it’s desirably, too. On the low end of the popularity scale is the cartridge filler. Cartridges are convenient and much less prone to get ink on the fingers of the user but the user has to stick to the ink and colors available in that cartridge from the maker. Next best filling system is the “converter” which changes a cartridge filling pen into one which can take ink refills from ink bottles, opening up the possibility of using any ink which comes in a bottle. Lever fillers are just about always the vintage way of filling a pen. A sac inside the pen is squeezed shut by the lever and then when the nib and its fill hole are immersed in ink, the lever is deployed and the sac engorges with ink. Lever fillers phased out in the 1950’s and the sac can fail causing some pretty awful mishaps. Piston fillers have a small drum like stopper which rides up and down on a screw mechanism. It creates a vacuum inside the ink chamber and sucks up the ink from a bottle that way when the end of the pen is twisted. Finally, a vacuum fill pen pulls ink into a pen when its vacuum mechanism is activated; it’s a quick action and very clean. The price of a pen usually goes up with the desirability of the filling system in the order I outlined above.
Size, nib width, and filling system are three big factors in the price and popularity of pens now and so you might say that the Montblanc 149 is the Holy Grail of pens circa 2012. Sporting a price tag of around $800+ it’s the pen to be seen with and it actually writes wonderfully well! Or you could investigate some of the very good pens at about $60 from TWSBI, a $25 pen from Noodler’s, a $5 pen from Jinhao, or the Pilot 78G (which is a truly remarkable bargain and a wonderful writing pen, one of the few modern pens with a sac fill).