After a running battle with MySQL, PHP, and phpmyadmin, I'm happy to say I've got a working Gallery2 install going. You can check it out at http://photos.visuallycreated.com if you'd like. At the moment, there's not a lot of content there, although I'll be moving over most (if not all) of my dA gallery shortly. After that, I'll have to deal with about a year's backlog of photos, but many of those are already sorted in Picasa to a degree.
Some people (who either use Gallery themselves, or have way too much time on their hands) might question why I choose Gallery2 even though Gallery3 is now released and stable. The short answer is familiarity. I've used Galley2 before, I know how it works and, more importantly, how it fails. Given that I didn't have firsthand experience with most of the rest of the software stack in use, removing a variable seemed sensible. It also made configuration a lot faster, as I already knew what I wanted and how to get there.
Having completed this, a lot of the back end for anything else web-facing I care to install is now in place. Apache/MySQL/PHP is the framework for a tonne of things, and most of the hard work there is done. I'm not sure how much of it overlaps with other planned projects though (diaspora I think runs on Ruby, and IRC and mail servers might at most use MySQL). We'll see what's left to do as the time comes!