Acer 4x/4x/32x CD-RW drive some years back. It was on sale with rebates at Best Buy, so I grabbed it. (Around $120 I think after all was said and done.)
Burned 90% coasters the entire time I had it. Garunteed coaster if burned at 4x. Higher success rate at 2x. Best at 1x. The Acer CD-RWs that came with the drive lost data integrity within days and I discovered that I had lost over a gigabyte worth of data that I had tossed on a few CD-RWs in blind faith.
Kept me away from burners for years.
Honorable mention: Hercules 3D Prophet II MX. The poor image quality scared me away from nVidia for years. The colors were always very washed and lustless in comparison to my Radeon. I also didn't appreciate how much of a gimp the SDR memory was in comparison to DDR until I looked at my own personal benchmarks. Overclocked to 220MHz SDR, my framerates at 1024x768x32 were barely higher than the TNT2 it was replacing. Obviously anything higher than that was pathetic. But that part was my own fault for thinking I could get away with an OC'ed SDR card into a DDR performance range. Cheap card. I got it around the $90 mark I think. But waste is still waste.