I love Cabel's FancyZoom. It's the only Lightbox script I would ever use. Most of the other Lightboxes that take like 5 seconds to fade and autoadjust the dimensions of the frame are just inane.
The only issue that I have with it is size. Cabel basically wrote his own proto/jquery in the process of writing this so it's pretty big. I'd suggest to people who use proto/scripta or jquery to look for a lightbox that uses that lib and is much more manageable in size.
