One of the biggest challenges we faced when we decided to try and come up with the "best" recipe for chili was to narrow the competition. There are so many different kinds of chili (Texas, New Mexico, Cincinnati, to name a few) that we knew we had to decide on a particular style and go from there.
Our choice was Texas chili, a beanless dish that goes heavy on the meat (usually beef) and favors the use of ancho chiles, which have a deep, sweet, raisiny flavor. Once we knew (sort of) what we were after, we could concentrate on making a great bowl of Texas-style chili.
While ancho chile powder will do, we got the best chile flavor by toasting and grinding fresh chiles. Flavor is also improved by adding bacon, which lends the dish sweetness and smokiness. Thickening helps, too, making for a smoother, softer, and more appealing sauce. (This can be accomplished with cornstarch, but masa harina--a type of corn flour made from sun- or fire-dried corn kernels--is preferred; unlike the cornstarch, it actually adds flavor while it thickens.)