Change highlight colour in Sublime Text 2
Found the theme files in this directory:

~/Library/Application Support/Sublime Text 2/Packages/Color Scheme - Default/(name_of_theme)


You can see which theme you are using by going to (from within Sublime Text 2) 

Sublime Text 2 menu&gt;Preferences&gt;Colour Scheme


and see which one is ticked.

Open the theme file and find the key that says:

&lt;key&gt;selection&lt;/key&gt;


not one of the highlight keys.

Go to a site that shows hex colour codes (like this one http://html-color-codes.com/) and find the code for the colour you want. Then sub your new colour code into the line below the selection key in the theme file, replacing the old hex colour code.

Save the modified theme file and it should work straight away.