It seems that we tend to get a new lightbox clone every few weeks or so, so here are some I’ve run into recently:

From this set, I find Shadowbox the most robust and visually appealing. Of course there’s always version 2 of the original lightbox that you can use. But if you’re looking for a gallery–type solution, take a look at Galleriffic — it has most of what you might want in a javascript–based gallery.