In this Google translation of a Portuguese page discussing the next version of MacOS X, I was amused to see that Finder windows will apparently contain a slider for controlling the size of applications' icons when folders are presented in icon view:
The Jaded Consumer notes that this is a feature IRIX (SGI's Unix running an X-Windows shell) offered standard in 1995. It was IRIX and its X-Windows GUI that first persuaded me that the firm that made user-friendly Unix would be in a position to make a mainstream operating system that would work -- a competitor to MSFT's offerings, and a solution to the high-overhead alternatives that have so long kept people warring with their machines to work.
Now that MacOS X allows the Finder (at least in some views) to display file names as long as Apple will allow you to name files (so you can make windows configured for you to compare files with such names), MacOS X has caught up to most of the best features offered by OS/2. (The per-folder custom background image might not be available, but exactly how necessry was that? By contrast, reading your file names without scrubbing the mouse over every file in a folder of hundreds is useful.) Catching up with the eye-candy of SGI's 1995 X-Windows might not be earth-shattering, but maybe in a way it's progress. (Considering that icons of PDFs look like the PDF, and icons of photos look like the photos, this is actually much more useful now than years ago when photos and PDFs were generic icons; thumbnail views of photos was the reason IRIX' GUI allowed scaling, if I recall.)
More important in Snow Leopard will be stem-to-stern 64-bit kernels and their associated improvements in in-kernel handling of memory (no more 32-bit kludges for RAM over 4GB, I hope). Performance improvements long postponed out of fear of breaking drivers that depended on in-kernel memory structures will materialize: since every driver needs recompiling, there's no reason to be held back by anyone's ancient drivers. Since my printer is supported by CUPS, there's no fear I'll have to replace it, either: CUPS will be provided in Snow Leopard, and CUPS will read the printer description file provided for my old LaserJet 6L, so all will be right as rain.
If Apple starts offering per-folder background image preferences, I'll have to start wondering where Apple got an OS/2 engineer. Until then, I think Apple's on a path toward improvement.
Incidentally, MSFT's price-based advertising (first discussed in connection with its "white paper") has hit a new snag: their featured "real-world" computer buyers and their interviews appear likely to be blatantly canned, and thus a sham. Apple's return punch doesn't pretend to offer non-actor shoppers, but is plainly in line with its existing line of "Get a Mac" advertisements starring John Hodgman.