I use Markdown when I'm writing content-heavy prose, like wiki pages or READMEs. When I need more control over the exact classes and tags, HAML is a good alternative to HTML.
In the case of Markdown prose, I don't /care/ what kind of HTML it writes. Headers, paragraphs, links, all taken care of. I write text, it gets run automatically through a parser/html generator (I use maruku), and I don't think about it. HAML is great for templates & layouts, when I care about DIVs and ids and classes, without being the wordy, ugly HTML itself.
In the case of Markdown prose, I don't /care/ what kind of HTML it writes. Headers, paragraphs, links, all taken care of. I write text, it gets run automatically through a parser/html generator (I use maruku), and I don't think about it. HAML is great for templates & layouts, when I care about DIVs and ids and classes, without being the wordy, ugly HTML itself.