I love drag-n-drop. I think every widget should have a drag-n-drop event, if only to display a message box saying, "What do you think you're dragging and dropping on me?? Fool!" It's another of winforms' draws for me--that, and I don't have to blog about AJAX. Heh-heh.
I've been Jonesin' for drag-n-drop. Jonesin'! And now that I'm a hardcore winforms coder now (though only a newb), DragDrop is just another event, another method, a few more curly cues.
JFO posts an excellent article titled "Handling DragDrop in 5 minutes." The MSDN DragDrop info to which JFO links is pretty good, too.