I’ve been happily integrating Gallery2 into WordPress lately and it’s working well. However, it’s overkill for someone who just wants to put up a few photos in a few albums (and doesn’t need fancy-pants watermarks, integration with shopping carts, etc.). Just found a few that look promising:

At first glance, it looks like Plogger is more of a multi-album gallery and SimpleViewer is a single album (and you can make more albums).