Well, ive been at it for 8 years now, and really all you need is:
html
php
mysql
javascript
css
And the rest of the fancy junk is for noobs who like to give everything special names.
If you need to load data without loading a new page, or seeming to not, you can use ajax, which is javascript, or an easier and more developer friendly method is to use a hidden iframe, and than you dont have to worry about stupid ajax errors.
As for xml, its not really something you have to learn... its simply customizable html.
Object Oriented programming, well your already doing that with normal javascript programming. As for adding classes and stuff to javascript... well that's not really necessary. I use classes all the time when i program software, but when it comes to websites, i have never created a class before.
JQuery is rather inefficient, and bad for people who have old computers. Plus it adds an extra 200kb to each visitor. If you have a website that gets lets say, 10 thousand page views a day, that is up to a max of 2 gigs of wasted bandwidth.
UML - i have no idea what it is, or what it does, and have never used it.
Pear - pear is just a php extension. For the most part, you will never need to use anything beyond the basic php language.
As for smarty, that entire library can be easily replaced with good programming, and the proper use of importing files.
well, that is just my opinion
i know... its long
