(Couldn't help it.) We've been using a wire mesh coffee filter for years. The mesh isn't quite fine enough, and we've always been left with a little sludge in the bottom of our carafe — not to mention a sludgy build-up in the machine that causes frequent, annoying leaks.
Before we broke down and bought paper filters, we decided to give the Coffee Sock a try. It works beautifully, even if it doesn't fit perfectly in the basket. The "Sock" immediately solved our problems, retaining the tiniest fragments of our coffee. We have not had a leak in weeks, and we didn't have to make room in our cabinets for a box of paper filters. Love it!