I usually end up writing with a pen because I find the greater level of contrast easier to read; I have pretty bad eyesight. Lately I've been using fine-point Sharpie pens and they're great for readability.

I do a lot of pencil drawings, though (http://orng.us/ob8yao) and I do find something magical about the feel of pencil on paper, and even the smell of the graphite. I can lose myself for hours. But if I'm writing, I like a darker line, which means softer lead, which means more smudging.... bleh.