Holokai is inspired by molokai Since I feel the contrast of molokai is too strong for eyes, I tweaked some colors of it to become the first version of this.
I think Holokai is the best dark theme for VIM on Ubuntu GNOME terminal, which has a Ubuntu purple color background. Set it to a bit transparent would be more comfortable.
Just copy the files to your .vim folder or use Vundle-like plug-in manager to do so.
To use this color scheme under x-terminal, you should enable 256 color support in both x-terminal and vim and also screen/tmux if you have one.