I have now installed an image gallery and wiki on this website. I was disatisfied with Drupal's built in gallery functionality and decided to give Gallery a go. Unfortunately, only version 1.x is supported on Ilisys, so it isn't integrated with Drupal. I especially like the remote uploads options and slideshows in Gallery.
I'm using MediaWiki, mainly to gain experience with it for work. I'll try to find some purpose for it eventually.