I'll like to thank everyone for contributing here. I've tried nearly everything and nothing's satisfying. Ballpoints and rollerballs are too liveless. Gel is the only satisfying thing out there, but this accursed place only has my favorite blue-black ink in 0.7mm, and I can never stand broad print. My handwriting has been looking unexpressive ever since I ran out of my favorite pens/inks, so I started to appreciate the nuances of writing.
I didn't want to venture out to use Uni Signo gel which is more slippery and too hard for me to actuate, leaving a mess. I prefer my writing strokes to have say, the velocity profile of a Bell curve, nothing angular or sudden, and definitely no discontinuities (ballpoints).
I considered pencil and lead, which is clearly the most economical - BUT, there's one thing which I can never tolerate about lead: it's glaring under a fluorescent light, I hate reading notes written in lead. Pencil lead is far too reflective. If any of you have done art, you'll know from comparing with charcoal that it is far more reflective than 'proper black', that's why you do shading with charcoal pencils instead.
Oh, I forgot to mention that rapidographs/felt tips actually felt better than gel in terms of smoothness and expressivity, but they drained ink too fast and weren't cost-effective... although I can't say my eventual decision was (read below).
So, simultaneously... I finally decided to become a physics and mathematics double major a few days ago. I decided to celebrate the occasion with something symbolic. And you see, musicians have their 'favorite' instruments. Artists have their finest brushes and paints. I'm kind of romanticizing here, but I felt that I should have a favorite instrument too! I laid down my mind, and bought a fountain pen, with a Pilot dark blue ink, similarly to the one that I love. Redsummers' experience was very helpful, I looked back here to justify my $180 purchase and that sealed the deal. I bought a Sailor 1911M demonstrator, like the one pictured below:
P.S.: I had a bit of post-purchase bias from knowing that Einstein used fountain pens strictly :P
^rhody: I don't have a formal writing style. I suppose it's a modified-notetaking-style with some cursiveness (for example, my pen only leaves the paper twice when writing 'variational principles' - just picking out a random phrase from the paper right next to me, once for the "t" and once for the gap). My level of 'cursiveness' increases with urgency.
ThomasT said:
Of course not. I use a pencil with an eraser. Don't you ever make mistakes? And then, if it's ok, I transcribe it via some math-writing program to a usb flash drive or disc. Pens are virtually obsolete.
I use cancellations for my mistakes. And that's it. It's actually refreshing to see your mistakes rather than hide them. (I even write in pen on some of my books.) I sometimes even write things like "Yes!" in my book, which really shouldn't be there for brevity.
I've been getting quite a number of praises for my live-TeXing speed, but the only thing that's keep me from 100% live-TeXing is that I can't generate graphs or diagrams with ease. I should probably find some time with MATLAB figuring out everything, or learn how to use a vector graphics program.
The other thing that's actually keeping me from live-TeXing is a sort of social pressure - for one, I don't want to give some of my professors the misunderstanding that I'm surfing facebook in class or something (once or twice I get that 'look' when I'm typing away at my keys), the other is that it's quite... unusual? I mean like, 95% of my classmates in my senior classes use pen and paper - the guy who actually live-TeXes is a graduate student, while exactly 100% of my classmates in my freshman-sophomore level classes are still using college-ruled sheets with pen/pencil.