will jpeg 2000 ever be supported in GIMP. A similar question was already asked in December 1999 to this list, however, situation has quite changed since then, and the standard is now fully specified (in its fist version at least). I once also read about patent issues, similar to Tiff, does anyone know anything about that? In the web-pages I visited I couldn't really figure this out.
I think that this new Graphic standard offers quite nice features and should be taken into consideration. One nice feature is 16 bit color, which probably will only be actual in Gimp 2.* (http://www.gegl.org/), however the wavelet compression and the possible regions of interests are also very interesting.
If you don't know about jpeg 2000, please see: