Yesterday I took a first look at jp2. It's truely awesome. It's smaller than jpeg and it also looks much better (I mean the lossy mode). For example hard contrast edges don't end up in a mess of jpeg artefacts. 80% jp2s look pretty much perfect and it's about 20-25% of the size of a png. However, the patent stuff seems to be still pretty much unclear. I guess it's not used much for that reason.