Right now the UI of Firefox and Thunderbird are a complex mess of iterations of previous versions. There are so many elements left over from previous versions that have not been updated, or do just not fit in with the overall design scheme. Opera has a really nice design that is uniform and used throughout the platform, and is very modern-looking for the revival of round corners, translucence, and 3D textures. It would be great if Firefox and Thunderbird could do the same as well.
