Allie recently turned me on to Chuck Klosterman and one of his essays entitled Nemesis*, where Chuck illustrates with his prosaic words what women and comic book fans around the world have intuitively known for years. Most everyone in the world has both a nemesis and an archenemy. It is here he brilliantly defines the difference between nemesis and archenemy.
According to Klosterman, a nemesis is some one you kind of like even though you despise them. You would probably have drinks with your nemesis and go to their wedding**, if invited. Your archenemy, on the other hand, inspires such hatred that you won't even admit to hating them for fear of giving them the satisfaction. If your archenemy died, you would throw a party and dance on their grave.
The funny thing is that, while my archenemy came to mind almost immediately, I'm having a hard time identifying my nemesis. I'm sure I've had a nemesis over the years and probably could have named one immediately in high school or college. Is that I'm too old for a nemesis right now? Do I only harbor long-term grudges that speak more to the level of archenemy? Maybe I need to meet more people so I can develop a nemesis.
*Also known as The Importance of Being Hated.
**Of course, you would also be hoping it ends in a bitter divorce.