WRT the "write for humans" anecdote, here's a good rule of thumb.

Write your title and content for humans, sure, but be aware that they aren't the only ones "reading" your content. Try to at lease slip a keyword or part of a keyphrase into your post/page titles (wrapped in H1 of course). Then use Thesis, Genesis, Hybrid, or AiOSEO/Headspace2 plugins to craft the doctitle. Users won't ever see that anyway, but it's what search engines look at before anything else on-site.

I'm not saying to stuff keywords in there ... I hate that, and I don't think it works very well ... I'm just saying to use it to rewrite your title to target your keyword or keyphrase.

That way, you don't have to look at this as an either/or scenario. You can write both for humans AND spiders and get the benefits from both.