I've written my bachelors thesis (mostly) with Markdown and Pandoc. You can just insert TeX commands in your Markdown and pandoc will recognize and pass them. I

I've written my bachelors thesis (mostly) with Markdown and Pandoc. You can just insert TeX commands in your Markdown and pandoc will recognize and pass them. It's really neat. I don't think I would have wanted XML documents as sources. I felt like Markdown was a successful step away from any XML-inspired tag formats. Most books don't have a complex hierarchy. They just have paragraphs and titles.