Sublime Text 2 comes with various colour themes. One of the best theme (in my humble opinion) unfortunately is not included so you have do download it and activate manually. This theme is called Tomorrow Night (with my favourite Blue edition).
All Tomorrow themes are made my Chris Kempson and you can obtain them from GitHub. In this article I will show you how to change theme in ST2 in Debian / Ubuntu OS. First of all you need to download theme and unpack it. Location, where ST2 stores custom stuff is can be found in your home folder:
Even if you wouldn’t know that, you can simply open menu Preferences and Browse Packages. From extracted package copy textmate folder. Textmate theme is compatible with Sublime Text 2 and you can use it in both editors. When you will do that, you should have new option enabled in menu Preferences / Color Scheme / textmate / Tommorow-Night-Blue. Select it and that’s it.