[baghali]

I personally enjoy being able to split panes vertically with iTerm2

[statico]

Indeed. iTerm2 has replaced tmux for me for local development.

[daxelrod]

Why not both? http://code.google.com/p/iterm2/wiki/TmuxIntegration

iTerm2 can intelligently communicate with tmux in order to present splits and windows are handled by iTerm2, rather than within the single terminal window.