I've just started using tmux and I'm having trouble with my colorscheme in vim. I've using the zenburn color scheme and it works fine with the default terminal settings in Ubuntu 10.04.
However, when I run vim in a tmux session the colors don't look good at all. I've done some searches to try to figure out what the problem is and one thing I found is this question where the solution involved allowing tmux to using screen-256color and removing the setting in .bashrc which was setting it to xterm-256color.
So I am curious what the difference is between xterm-256color and screen-256color but I haven't found a good explanation yet.