what i really liked was the zip upload for images which saved me a lot of time. in the past i had to use galleries getting images from folders (which i upload by ftp) when i had lots of images and then i couldn't assign a description to those images (only using text files which is not very user friendly for website managers and end-users). Ignite Gallery takes care of this with the zip upload.
It's really simple but at the same time extremely customizable and it can easily be adapted to any project you need. your gallery no longer needs to be flash to look good, plus i've used it in a multilingual site and translated all photos and categories using joomfish contentelements.
I am definitely using Ignite Gallery again.