I use VIM and iTerm 2 on OS X 10.9.1. In my .vimrc, I have the following (note that I'm using the molokai colorscheme, you would switch that with 'evening'):
let &t_Co=256
colorscheme molokai
syntax on
Those settings worked best for me. Those settings also resolved some issues I was having with colors while using VIM in a tmux session.
Also, in iTerm's preferences, under Profile > Whatever Profile You're Using > Terminal, make sure "Report Terminal Type" is set to:
screen-256color
Hope that helps.