The best source of info I've ever found on dealing with vid playback issues is the Guide that Ian Roberts (AbsoluteDestiny on LJ) and Trythil have developed. The guide is fantastic and I recommend that every vid watcher bookmark it. It is extremely comprehensive, yet written very clearly, such that even video newbies should be able to follow it without too much trouble. It covers Windows, Mac, and GNU/Linux systems. The guide can be found here:

How to Play Those Damn Videos!
  http://www.animemusicvideos.org/guides/playback/

The very best player that I've found to handle a wide range of vid formats is the VLC player. It's free, no spyware or malware, is updated regularly, and plays nearly every vid format except Real Media. I use it as my default vid player, and the VCL player has NO PROBLEMS with any of the vids that you've posted online so far! The color is not washed out, as you're saying that QuickTime has done. (Gwyn R has posted about that problem with QuickTime before, and also recommend the VLC player as a solution.) I already recommend the VLC player to everyone I know who watches vids, especially since it is user friendly in that it doesn't require extra codec installations which frequently frighten folks off from updating other players.

The VLC player can be found here:
  http://www.videolan.org/vlc/

Here's a list of features and supported formats - including those that you've used to encode your online versions.
  http://www.videolan.org/vlc/features.html

Take care,
Karen Applegate