FCKeditor (which really stands for Fred CK Editor) is a javascript based html editor. It doesn't look dissimilar to Microsoft Word built into a website. It allows you to nicely format text that you can insert into your database.
I've been testing it to see if I can make use of it in my yet to be started admin panel. So far I've been very happy with it. There are only two problems with it:
There is also a Source button that you can click to view the source code of the text you are writing, which can be useful. Also it is very easy to integrate into php web sites.
There is a demo here if you're interested.
Oh no sorry about that, that wasn't FCKeditors fault. I was just playing around with stuff.
The markup is pretty clean. I might post it here in a sec.
I've not used Markdown, although it seems similar.
I think josh tried it out once; although I don't think he was overly impressed by it, don't remember.
Josh?
No, Markdown is just text formatting stuff, not pure WYSIWYG. You can get JavaScript to render Markdown in realtime, but it's not a true WYSIWYG editor like FCKeditor is. My bad experience with Markdown was the result of a poor implementation in WordPress, I think, not Markdown itself. That's by John Gruben of Daring Fireball isn't it? I seem to recall trying an online demo there which was excellent, but it just wasn't the same when I tried with the WordPress version. There's one thing to be said for rolling your own!!
Well, FCK looks pretty nice. I may have use it when I'm blogging away from home, and without Markdown.
Looks like it broke your list, though... I'm a little worried about the markup it produces (or doesn't produce, in this case).