The endless headache:

My pages looks different to how it was in [Word/TinyMCE/Xinha]

Since the dawn of word processing, the temptation is to treat an editor like a typewriter and arrange the appearance of the text to match the meaning you are trying to convey.

The html -> x(h)tml revolution was an attempt at seporating the style from the markup, but most word processors (exception LyX), email composers, blog post composers etc still follow the typewriter paradgm. Or you can slave away with BBCode or raw html, but it's a PITA.

Enter my new friend WYMeditor, lots of clicky buttons, but designed explicitly to deal with what you mean rather than how a page will look, and leave the style down to the CSS of the rest of the site.