I did a quick search and found the url for PHP Triad at
http://sourceforge.net/projects/phptriad , which I would recommend to anyone with Windows so they can have the Apache server, PHP, and MySQL installed on their computers. I think it also comes with MySQL-front (but if it doesn't, you can download it at
http://www.mysqlfront.de ), which is a great windows program and front end for MySQL, though I prefer their older version 2.5 to their newer one (2.6) because, for some reason, it works lightning fast on my system (whereas their 2.6 version can get slow). PHPmyAdmin is also a nice MySQL front end that you actually run and access on your server, which is convenient.
I don't think I've heard about
PHP: Fast & Easy Web Development. One of the best books I came across when I first started PHP is Sybex "Mastering PHP 4.1". The first few chapters provide the best intro to PHP I've seen. The PHP "Bible" would have to be the "PHP Manual", which is posted at
http://brainmeta.com/phpman/ , but I would highly recommend that you try to obtain the .pdf version through a file-sharing program like Bearshare. In retrospect, this PHP Manual (the pdf version) has been, by far, the most helpful and oft-used piece of PHP literature that I've referenced. The html version is also found at
http://php.net , which is one of the best sites for PHP around (
http://phpfreaks.com and
http://codewalkers.com are also worthwhile).
About Content Management Systems (CMS), I have never deeply looked into these packages. I know there's phpnuke and other packages that, more or less, are complete CMS's.... I don't know what your thoughts are on this.
what a question!

I don't know about the 'average PHP script', but in my limited experience, I've used a lot of the following loops and functions:
include, echo, die, if, else, switch, break, for.... hmmmm, that's all that comes to mind at the moment, but I'm sure there are more. Also, knowing all the details of forms, tables, and MySQL are essential for many scripts, though not for your average script. Javascript and DHTML also come in handy often.