I finally refurbished the headlight lenses on my 2000 GTI. The lenses don't look brand new, but they are much improved. The lenses had gotten so hazy/foggy that I could barely see while driving at night. I used the Meguiar's headlight restoration kit; $19.99 at Wal-Mart.
Before (Pic taken last summer)
After
Close-up
Before (Pic taken last summer)
After
Close-up