Good point, I guess a point to learn is not to rely on coverflow or preview for your real work and only rely on them to get the right selectionI'd say preview takes account of the color management embedded in OS X, while coverflow will try to render the pictures faster, without dealing with it. Hence the difference in color and contrast.
I suggest iPhoto since its free or you could use Aperture or Lightroom if you feel you need a proper photo management software.What would be the best viewing program? Seems a little much to be forced to open Photoshop each time I wanted to view some pictures.