JVC XV-S300 DVD Player
Didn't properly play 90% of DVD's I tried!
Of the 20 DVD's I rented or borrowed from friends, only 2 of them played properly.  The other 18 had a wierd problem where the brightness of the picture would fade in and out.  It did it while playing movies, while paused, and in the menus.  I called JVC customer support to troubleshoot the problem and they informed me that it was a disk specific problem.  Since 2 of the disks worked fine, it's not their fault and there's nothing they can do.  These are DVDs that worked fine in other players.  Any machine that can't play 90% of the DVD's I try is worthless...