You have a few options when it comes to designating family heirlooms. You can put it your will, and then you don't need to deal with any fuss, and when your wishes are in writing they're hard to disregard. That might be more difficult for your descendants, though.
One way to potentially avoid hurt feelings, arguments and impossible choices is to make a day of it. Some experts recommend getting everyone together so they can claim what they want. Taking turns with colored yard sale stickers, each immediate family member claiming an item in turn, is a popular way to do this.
One of the biggest benefits with this method is that you're taking grief out of the equation. Grief can make feelings very raw and make losing a cherished heirloom seem like the end of the world.
If you simply can't bring yourself to choose who gets what (and tell them about it), you can always donate it. Small museums may be interested in an antique, and charities might take a piece of value and sell it. That way, at least your kids will be mad at you and not at each other. They'll be spending Thanksgiving together long after you pass on.
For more information on family heirlooms and related topics, look over the links on the next page.