[mmatants]

Semantic = for developers. I.e. not in the "make it nice for web crawlers" sense, but for readability of template code.

So for my own workflow, I have been quite comfortable being a "semantic stickler", where markup is written first and with only a general wireframe. CSS classes are added sparingly, to mark separate areas of concern for LESS/SCSS grouping. And then styling work begins, during which I try to avoid adding presentational fluff to markup at all costs. It's hard, but CSS3 allows a surprising amount of power.

The rule of thumb is: clean template code is worth dirty CSS hacks. CSS is going to be shit anyway, due to its inherent qualities as a language. So might as well make templates awesome.

And again, this is for developers' sanity more than anything to do with "semantic web" or whatever.