10.4 was such a beautiful operating system. I really believe that Apple had the best operating system out there for the short window that 10.4 was around.
The ease of use is so much higher than recent MacOS versions it's not even funny.
But, in terms of visual design... I don't think it's as pretty as Leopard, but what I find intriguing is how well it matches the hardware design of the era. On a Powerbook or PowerPC iMac, I can imagine how the contents of the screen would perfectly match the hardware that framed it.
I don't think Apple has done anything quite like that since...