OS X bash profile. These are the very basics, without much configuration.

gistfile1.sh

###
### .bash_profile
###

export PATH=/usr/local/bin:$PATH

# Get the aliases
source /Users/ethan/.bash_aliases

# Enable colors on the command line
export CLICOLORS=1

# Add ~/.bin to $PATH
export PATH=$PATH:/Users/ethan/.bin

# Set TTY.
if `tty -s`; then
   mesg n
fi

# Colored CLI prompt
GREEN="\[\033[0;32m\]"
BLUE="\[\033[0;36m\]"
WHITE="\[\033[0;37m\]"

export PS1="$GREEN\h:$BLUE\W$WHITE\$(parse_git_branch)\$ "

# Git helpers
function parse_git_dirty {
  [[ $(git status 2> /dev/null | tail -n1) != "nothing to commit (working directory clean)" ]] && echo "*"
}
function parse_git_branch {
  git branch --no-color 2> /dev/null | sed -e '/^[^*]/d' -e "s/* \(.*\)/[\1]/"
}

# Git completion
source /usr/local/git-completion.bash