Choice of WYSIWYG-editor

[eluser]Johan André[/eluser]
Hey!

I'm developing for a project which will release later this fall.
Right now I need advice on what editor to use.
It must product valid XHTML and needs no cool features.
Only thing it needs is marking of headlines, "bold", "underline" and possibility to create links.
I like the way a standard textarea work together with the auto_typography()-function (double linebreaks creates new p-element).

I've tried SPAW and TinyMCE and the output is not always good.

I'm really serious about even getting user-input data valid.
I could use bbcode-style input but that will confuse the contributers. I would like it to be:

1. easy to use for complete idiots (WYSIWYG)
2. lightweight
3. valid xhtml output

Any ideas?