(Sarah Read is an author, editor, yarn artist, and pen/paper/ink addict. You can find more about her at her website and on Twitter.)
The Pentel EnerGel is arguably one of the best pens you can find in any random stationery aisle. They're widely available, and they might even be stocked in your office supply closet at work. If not, I suggest sneaking some in there.
The EnerGel ink is a blend of gel and rollerball ink. It's known for writing smoothly and drying quickly. It is sometimes described as a smudge-free ink, though I found all of the colors smear a bit--some more than others. While it does dry more quickly than some gel inks and claims to be good for lefties, I worry that it may smear when a hand is dragged across. It does okay with highlighter, but not great. Even the dry ink smudges a little, and will leave a residue on the highlighter tip. But the text was still clear, and it didn't perform any worse than most pens under the circumstances.