ranger (a curses file manager that uses vi/vim bindings)

A multi-column display allows viewing in a tree-like manner. You can
preview the content of the selected file or directory, copy or move
files around with the VIM-like commands dd and yy, execute predefined
applications when opening a file, etc.

Everything is fully customizable and written in Python (2.7 and 3.1
compatible) using curses for the text-based user interface.

Optional Helpers:

w3m (for inline display of images)
atool (for listing files inside archives in the preview pane)
highlight (for coloured previews)

(Note that highlight is used by default. Pygments requires editing the
preview script 'scope.sh')