I've tried SimpleViewer , Gallery2, Gallery1 and a few custom utilities for image displays. I would have to say Gallery2 is great for quick turn around. However Gallery2 can be tricky to integrate into a website.
Lone Star Regional
http://txfirst.org
and 2587 Afrobots
http://afrobots.org
Both have Gallery2, there are a wide variety of themes you can choose to make the image layout work for your site.