I've always worked in Black and white, originally using pencil. I eventually moved on to ink because I liked the permanence it provided.
The style I'm currently using came about from wanting the shading and lighting you can achieve with a pencil, from a pen. The best description i have been able to come up with is "controlled scribbling". It has it's limitations, but I really enjoy it because no matter how hard I try it will always be imperfect.
I usually start with a very simple drawing, concentrating on filling the page rather than content. I want my style to be the theme that ties all my work together, so I don't pigeonhole my drawings content-wise.