alt Hacker NewsSnow Leopard was my favourite. Was also the version I first started out with as a Mac user, so there's probably a nostalgia component that influences that opinion.
What I do know is that in the uniform-looking icons we have in the current dock, I seem to find myself hunting for the right icon to click a lot more than I have in the past.
The icons reflecting on the isometric bar is also far more tasteful than any of the semi-opaque tricks they're doing today. I agree that skeuomorphism was getting out of control back then, but the only alternative wasn't to go brutally flat with everything, everywhere.
Aesthetically I think the dock peaked with 10.9 (Mavericks).