I'm not sure if this was suggested before, but could be very handy:
I use ST2 mostly for developing for the web, which means I always have PHP, JS, CSS files opened.
It could be very helpful to have each type of file a different background color, so it will be easier to distinguish them from each other.
One more suggestion that I have regarding tab colors - Aging tabs.
I actually got this idea from a firefox extension ( addons.mozilla.org/en-US/firefo ... ging-tabs/).
Imagine having many files opened, but some of them are not currently in use, it would be easier to distinguish the active ones from the others if the background of tabs that are not in use will start to fade away.
I've photoshopped a screenshot to demonstrate both suggestions:
as you can see, CSS tabs are bluish, JS tabs are reddish, and I've left the PHP tabs gray.
The 2 last tabs are 'aged', and are faded out a bit.
I'd love to see these features in ST2