Turtle91 we are not going to set the Thames on fire here as I totally agree with you! Moreover, crankypants has nailed it perfectly: the best thing is to use what we are used to.
And this exactly what I do for html, using a text editor (usually NoteTab Light and some clipbooks) and applying needed codes through it: very simple and effective.
Though, codes used in markdown are also easy to remember (at least for me, but I have only one set to deal with

) even if there are some variations in sets.
Code:
Borow from WriteMonkey help card
Phrase emphasis
**bold**
*italic*
or _bold_ / _italic_
Structure
Heading 1
=======
Heading 2
------------
or
# Heading 1
## Heading 2
### Heading 3
...
###### Heading 6
LINKS
[link text](http://blabla.com)
ORDERED LIST
1. First
1. Sub item indented with TAB
2. Sub item indented with TAB
2. Second
3. *Third*
UNORDERED LIST (use -, + or *)
- First
- Sub item indented with TAB
- Sub item indented with TAB
- Second
- _Third_
INDENTED PARAGRAPHS (BLOCKQUOTES)
> This paragraph is indented
>> This is nested indented paragraph
HORIZONTAL RULES, PAGE BREAK
--- , +++ or ***
IMAGES
! [Alt text] (http://blabla.com/img.jpg)
Anyway, I don't care here to own the truth, I just want to say again that markdown can be fun to use and useful for some kind of projects and a few people.