I've been a stickler for Adobe Flash as a drawing tool as far back as Macromedia Flash 4.
I've tried other vector-based illustration tools like Illustrator, Inkscape and the like over the years but I've never found another tool that's as good as Flash with one simple concept: Free-form, deformable vector shapes without pivot points that aren't treated as "paths".
If you know what I mean by that, in ten years I've never found a tool that's as good at taking your drawn shape (line, polygon, closed) and just letting you grab an edge, pull/tweak that edge and having one side of the drawing warp like it's being pulled.
It's a fantastic and very intuitive way for a very left-brained person like me to get drawings looking how I'm happy with. I'm not being self-deprecating when I say I'm nowhere near as talented as most of you fine people from what I've seen, just practical. I'm a programmer, not an artist. Flash's vector smoothing makes up for my unsteady hand (I'm also left-handed, yet use a mouse with my right-hand... Go figure) and having the ability to layer elements and tweak/distort/scale/place drawing elements independant of each other goes a long way to helping me get on screen what's in my mindset.
For comparison,
this is one of my few traditionally hand-drawn comics (I was experimenting) from 2004. All my new stuff is back to vector-based, as to be honest it's much easier for this lazy programmer than actually learning to draw properly ;-) I do of course like a challenge but sometimes I need the familiary to get myself in drawing mode.