Philips DVP642 DivX-Certified Progressive-Scan DVD Player
Plays everything so far
I haven't found a DVD-R or +R that it won't read.  Also does a surprisingly good job playing DivX/xvid files.  The only .avi files this player won't play are ones encoded with QPEL (advanced motion compensation option).  It is an option that you can enable when encoding files to DivX or Xvid, but few people use it because it takes 3x longer to encode and only yields marginally better video quality.