I am getting a bit confused about the differing abilities of the different Blu-ray players entering the market.  Some seem to be able to play different forms of video and audio on top of normal dvd's and blu-ray disks.  Can anyone make a list of what players play other disks: cd's, dvd-audios, sacd's etc.  I know that there is not a universal player, but I would like to eliminate one or more of my players if I add a bluray player.
Thanks
Bob