Having a programming background, I find CSS a bit limited in my developing workflow. It does not ease the structural organization, and DRY concepts I’m used to. And the expression is now considered evil!
I have found LESS, a super-set of CSS that fits my needs, specially the use of variables, since I repeat the same color over and over again in my code, and I want to change it in just one place.
The main problem is that it requires code to be compiled (or interpreted) to CSS. It is not a big problem in my sinatra development, but there isn’t such a plugin for Django written in Python. It could be compiled via the command-line, but typing runserver wouldn’t do the trick then.
I really wish CSS evolves along with browser support, at least for the use of variables, that I miss like hell!