I like the Dark version best, EXCEPT the default blue being used by the system is nearly unreadable for me... example in Spark's signature, you have "deal with it, reddit" in blue and it is difficult to read. Ditto on URLs to other web sites listed in posts. I can read it if I highlite it as if copying it as the letters turn white on the blue background, or if it is a link, it turns gray on the charcoal, both of which are easily readable combinations for my eyes. As a curiosity aside, what was reddit bitching about?
Probably different eyes on different people. I saw where someone mentioned that gray in some places was unreadable, but I can read the gray text that Spark is using in his signature (name and owner of bladeforums segment) with no difficulties.