I started with the evening colorscheme included in the distro, and tweaked a
few colors to my liking.  Then I decided to do a major overhaul and give the
whole thing a desert evening sort of feel.  I find it a very pleasing,
easy-on-the-eyes theme.

Screenshot: http://hans.fugal.net/vim/colors/desert.html

Get the latest version at https://github.com/fugalh/desert.vim
Put in ~/.vim/colors or (<your-vim-dir>\vimfiles\colors on Windows) and do
:colorscheme desert

I mostly don't maintain this anymore. Occasionally someone has a tweak
suggestion - I recommend forking this and sending a pull request, or not.