Many clients require photo galleries to showcase some aspect of what services they offer. We used 'lightbox' effects to make the user experience rich and ensure a professional look. These can also generate timed slideshows to step through a large number of images.
The effect is quite impressive and adds 'pollish' to a site.
More recently we've added some new tools to our repertoire that allow us to give clients the ability to upload their own photos one at a time or in bulk, and build slideshows dynamically based upon what is on the web server at that moment in time.