Outstanding work by Glamour's Smitten blogger, Joanna Goddard. She asks one of the most pertinent breakup questions: to be nice or not? (BTW: Please check out her post, she is way more eloquent about this than I am, and the comments are pretty outstanding.)
We (Americans and other genial peoples) are conditioned to generally "be nice." Sometimes (MANY times) this niceness is counterproductive. Such is often the case with breakups. After lowering the boom on someone you love (or loved), you've gotta figure out if you're going to be nice to this person (and foster hope against hope of a reconciliation) or you're going to give this person the final Heisman*.
Obviously, every situation differs. Some people can remain incredibly close friends with their ex (like on The New Adventures Of Old Christine, you know that show with Elaine from Seinfeld and Wanda Sykes from whatever it is she's famous for). But for the most part, proximity is a recipe for either reconciliation or the trap of yo-yo dating.
Jack Black's character in High Fidelity, phrases it best, "Is it better to burn out than fade away?" The problem with the fade-to-black is that it takes longer (sometimes way longer) than an immediate cut to "FIN." Unfortunately, at some point in the past 40-50 years someone invented the concept of "closure." And now weaning someone off seems like the humane thing to do… an opportunity to let them know that, "golly, you're great. It just didn't work out even though I think you're great and the next person to come along is going to be one lucky ducky."
It's up to you if you're going to rip off the band-aid or ease into the hot tub**, but whatever you do, make sure that you're doing it for the right reason; such as revenge or wanting to prevent them from dating someone in case you change your mind. Please keep in mind that if he (or she, I guess) is being "mean" to you, it probably does mean he (or she, I suppose) hates you, it's just that they're need to get over it. Happy breakups, gang.
*Note: Unlike regular breakups which take time to stick, the Heisman is forever (unless you stab your ex-wife and a waiter).
**Note: I feel free to mix metaphors and, like loving Brian Piccolo, you should to.