Bleached paper filters are the white ones we've all seen. Bleached using either chlorine or oxygen, these won't pass on any papery taste into your coffee. That said, the bleaching process does create waste and uses chemicals.
The brown-colored, unbleached filters are much more environmentally friendly, but some people worry the coffee filter paper will taint the flavor of the coffee. If you're worried about that, too, you can rinse the filter with hot water before brewing.