For me personally, i dont really look at the galleries inside a site if im actually surfing it, i go right to the movies although, the webmaster in me says to put somewhere between 16-25 on a single page.

Any more than that and i think you are overwhelming the surfer.

Another thing, if a set contains upwards of 50 pics in it for example, you actually give the surfer the impression that there is a lot more inside the site, one set could potentially be equal to 3-4 pages of images

Regards,

Lee