CMS-Bliki requirements

For a project I'm working on, I'd like a system that has both wiki and blogging capabilities. I gather that concept is recent but not new. The term I've heard is "bliki."

It turns out that there are lots (and lots) of systems (including CMS, blogging, news/article management, and wiki systems) that have many of the features I want, but I haven't been able to find one that seems exactly right. Here are some basic requirements I've developed. Any suggestions about possible systems (and any comments about the requirements) would be welcome.

If it were open source, that would be even better!

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Requirements

0. Web based.
0.a. The system should seduce users into wanting to use it.
0.b. Very intuitive interface.

1. Wiki or otherwise easily user-editable pages
1.a. WYSIWYG editor. Wiki notation is a less preferred second choice. The primary users will not want to learn formatting rules if they can avoid it.
1.b. Spell check.
1.c. Virtually any HTML tag acceptable, with HTML help.
1.d. Flip back and forth between HTML and "preview" views.
1.e. Pages with different owners and protections.
1.f. Pages should be able to link to each other easily.
1.g. Page creation (as in wikis) simply by referring to a page that doesn't yet exist.

2. Blogs with feeds.
2.a. Multiple separate blogs for multiple users.
2.b. Cumulative blog that combines all blogs in one feed.
2.c. Blog(s) and wiki integrated. A blog entry also can be a wiki page.
2.d. Wiki page changes syndicated as a blog feed.

3. File (document, image, etc.) upload capability.
3.a. An easy way to link files to pages that discuss them.
3.b. An easy way to refer to files from (multiple) pages. Files are not just an attachment to a single page.

4. Elegant look and feel
4.a. Fixed-width text areas
4.b. Some color, but subtle--but not too subtle as in some wikis.
4.c. Flexibility in making "theme" decisions.
4.d. Well thought out font options

5. Site navigation
5.a. Text search capability
5.b. Traditional tree structure
5.c. Category structure
5.d. Date structured archive for blog entries
5.e. Site map perspectives both as text and as clickable expandable structure.

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Here is my current list of candidates: Candidate Bliki-CMS's