We have started using unbleached coffee filters in my house. When you think of pouring hot water over bleach into your coffee, you can imagine how scary that is! I'm not sure I notice a difference in flavor -- I haven't done a side-by-side comparison.
I used to use almost anything I could lay my hands on when I ran out of filters, including paper towels with printed designs! I'm lucky I didn't rot out my insides.