Can we some how use color labels on icons like OS X??
Something like this:
There are 2 options which resembles Mac OS very closely, both designed from similar code
UPDATE 2 I tried both Marlin and Pantheon Files (from other Stack Exchange contribution, see below). It seems that Pantheon files makes it easier to switch over from Nautilus. I am using Ubuntu 12.04 LTS.
Installation of Marlin
Option 1: Marlin with Dropbox / Ubuntu One support
Option 2: what I have tested without dropbox/ubuntu one support
According to the website, it is rather new and might have issue. Check out this article with some nice pictures showing how similar it is to Mac OS X file and folder color labeling.
Installation of Pantheon File Browser:
For Dropbox or Ubuntu One support, add the plugins:
It is possible to assign additional custom icons to files and folders in Gnome (smaller icons which are overlayed on the "normal" icon of a file or folder). Functionally it is equivalent to color labels from MacOS, I believe.