wysiwyg editor recommendations?

[MoMan]

I have just finished writing a homepage CMS system that's loosely integrated with vb, and was looking for standalone a WYSIWYG editor solution instead of having to use plain old text areas.

One requirement I have is that the editor must retain any embedded php code in the text if you switch over to code mode - those I've played around with all seemed to comment it out.

Thanks for any pointers!