Yeah, I used the UNO workaround for several weeks, so all of my applications looked the same way. While working with one interface design I realized that it's easier to have "a lot" of different themes, so I could better recognize the running apps. It is very useful that Firefox, Vienna, Mail and other apps which I use at an everyday basis look different. It makes things a lot easier!

It wouldn't be so nice if Apple would introduce one design in Leopard, but these are just my personal 2 cents.