Quicktime won the last test but can only encode at a constant Bitrate. I also think that ogg vorbis is going to be in for a rough ride over the next 18 months. The sudden advancement of aac/mp4 has left it by the wayside somewhat especially with still real no hardware support
I don't use Winamp or Itunes either - on the PC Itunes only works for Windows 2000+ and is a 20mb download at that!