there was once a plugin for seditio/cotonti that rocked! it was called Usergalley (usergal) and is still live on: http://urbancrusaders.nl
it has in my opinion everything a gallery needs. The only thing missing is a way to direct the userinput to categories.
My personal feature list would be:
admin can set main categories
users can add photo's to a given category or a own folder (which then becomes a sub-folder of the category).
ablility to display most recent and/or best voted and/or random picture on index (a bit like the gal of Kort)
