git - colored diff, branch, etc by default

See color.* options in the git config docs:

$ git config color.branch auto
$ git config color.diff auto
$ git config color.interactive auto
$ git config color.status auto

Or, you can set all of them on with the color.ui option:

$ git config color.ui true

or (global)

$ git config --global color.ui true

Links

git book

Color highlighted diffs with git, svn and cvs