I have only little knowledge about LaTeX, basic formatting, basic math fomulae etc.. I found that LaTeX is hard to configure to my own flavor. Recently, I've heard about Docbook, which is also a typesetting mechanism, but much easier since it uses XML. So, if my main job using LaTeX/Docbook is writing a simple document (not a class book) with some mathematics, and I want easy configuration, and a highly constomizable application, which one is better, and is there any good book on Docbook?
Answer
DocBook isn't "a typesetting mechanism". DocBook is all about separating presentation from content. DocBook only deals with content; it's used to create an abstract representation of a book, article, etc. There are numerous tools out there which layout DocBook according to predefined templates. Some of these tools use LaTeX. AFAIK, O'Reilly uses a slightly modified version of the DocBook language to author their content, then they feed this XML into custom scripts that integrate with Adobe FrameMaker to layout their books.
LaTeX is essentially an attempt to separate presentation from content within TeX, but it doesn't quite achieve that goal IMO. Presentation is still mixed with the content in most cases. I think LaTeX is currently the best open source tool for laying-out paginated documents. However, proprietary tools like InDesign have many features (like good OpenType support) that TeX doesn't have (XeTeX kind of adds OpenType support). Either way, if you're writing a book, I highly recommend using DocBook to author your content rather than LaTeX.
That said, it sounds like you're writing short, one-off documents with a bit of math. I think LaTeX is probably your best choice. If you need lots of customizability, you might need to use Plain TeX as opposed to LaTeX, but it's going to require quite a bit of work on your part.