As it turns out, Apple programmers could not leave well enough alone. They disobeyed the original “no new features” mantra. As they pored through all the bits of Mac OS X, they kept stopping and fixing little things that had always bugged them, or coming up with neat little ways to make things better. So:
The Mac now adjusts its own clock when you travel, just like a cellphone. The menu bar can now show the date, not just the day of the week. The menu of nearby wireless hot spots now shows the signal strength for each. When you’re running Windows on your Mac, you can now open the files on the Macintosh “side” without having to restart. Icons can now be 512 pixels (several inches) square, turning any desktop window into a light table for photos.
State of the Art – A Leap Forward With Snow Leopard – NYTimes.com