Thunar is a lightweight file manager with a very light memory footprint, a less cluttered layout and pretty much all the features one needs in a file manager!
Installing Thunar does not remove Nautilus so feel free to try it and see if you prefer it.
Installation
You can install Thunar using Add/remove, Synaptic, Ubuntu Software Centre or the good old fashion terminal: -
- sudo apt-get install thunar
- http://dl.dropbox.com/u/1115768/defaultthunar
- chmod +x defaultthunar
Switching back
To revert back to nautilus as default file manager simply run the script again: -- ./defaultthunar
Source:-
https://help.ubuntu.com/community/DefaultFileManager

