I find that trying to nail down "list" to mean something very specific like you have done just runs into problems down the road, though. For example, you say "(1,2,3) is not a list" but that contradicts parts of the Perl documentation. I understand what you mean in the context of this discussion but I think it is important for people to come away from the discussion and realize that many of the things that you say about "lists" above won't match things that a lot of other people (and documentation and books) are going to say about "lists" (because they are using a different definition of "list" than you).
See (tye)Re: @_0 vs. $_0, (tye)Re2: tr doesn't *really* use a list, (tye)Re3: tr doesn't *really* use a list, (tye)Re2: List context or not?, and (tye)Re3: List context or not? for my thoughts on "lists" in Perl.- tye (but my friends call me "Tye")
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>