The Mac I use at the agency where I freelance just got upgraded from Jaguar to Panther. I like it immediately. A smoother interface. Subtle differences really, that have a significant impact on my work experience. Fonts are crispier, something I appreciate more as I age. I have noticed that small fonts on web sites are more difficult to read than I remember. A good reason for web designers to specify fonts with browser-resizable ems, rather than absolute pixels.
I am waiting for Apple to come out with an OS designated “Fluffy Persian Kitty”.