I was rebuilding this site and I decided to use Fancybox 1.3.1 (the previous version which I used was 1.2.6). Surprise: it's completely broken in all versions of Internet Explorer (from 6 to 8)! IE doesn't show image controls, so you cannot close an image or open another one in a gallery or slideshow. Even worse, captions are without background in IE, so your text will shine through. Fine. Eventually I came up with a rough solution: using Fancybox 1.2.6 instead of 1.3.1. Oh well...