Tiger is cool! The other neat thing about the visuals is, if you think about Apple's industrial design in that era, the UI feels a perfect extension of the hardware itself.

And as much as I love Mavericks, I agree, I would absolutely jump to a Linux distro that recreated the experience faithfully. There really isn't anything though, especially when you add in the larger app ecosystem—I like using Aperture a lot more than Digikam, for example.

Edit: Oh, and:

> and by then sidebar item icons had lost their color

But you can bring the color back with the ColorfulSidebar SIMBL plugin!