I use Bic Mediums at work... the thing is I have a habit of biting the ends. I bit the end clean off my current one the other day, and wound up with a mouthful of plastic shards.

I like gel pens, but they tend to smudge. I also love Berol Handwriting pens (a step up from felt-tip; we used to use them at school), but they have a tendency to dry up so that you eventually have to hold them at a 180 degree angle to get any sort of sense out of them; they become useless and uncomfortable at this stage. But put the caps back on and it should be fine)