Here are some stuff that i have dabbled in or I have used. There are also links to the various components I have used to put together this website.

Yapig

Yet Another Php Image Gallery - The PHP component I have used for the photo gallery. A very easy to install and customizable component that is available for free under GPL. It has all the features that I wanted, without a lof of bells and whistles. It was very easy for me to modify and add some new features. For e.g. YaPig uses GD2 that normally comes compiled into PHP for thumbnail generation. But on my webserver, the PHP installation had GD 1.6 and this version of GD supports only 256 colors. So I modified the code to use NetPBM instead. I looked at how Gallery uses NetPBM and was very easily able to integrate NetPBM into YaPig. Among other mods that I have made to the installation on my site are a pop-up dialog for adding comments and ability to change captions for all pictures in an album. I have submitted most of the changes I made back to the developers.
Check out YaPiG's Homepage.

bBlog - is a very powerful blog publishing system written in PHP and again available free under GPL. It requires a MySQL database and uses Smarty for templating and makes it very easy to create new templates. Installtion and configuration is very easy and well documented.
Check out www.bBlog.com.

PicSizer is a Windows utility for resizing images in batches and individually. It has a nice interface and very easy to use. I use it extensively to resize my pictures before I upload them to the gallery. Its available for free from AxiomX Software