Native Web browser
Bash Internet Explorer all you want, but it's gotten a lot better ever since Firefox hit the scene, and it's easily the best Web browser natively available on any major desktop operating system. Admit it: Safari ain't great. Some Linux installs run Firefox or Chromium out of the box, and that's excellent--except for the fact that many Linux installs run a lesser browser such as Midori or Konqueror. Luck of the draw, I guess.
Chrome OS ships with Google Chrome (duh), which is better than IE in almost every way, touch versions aside--but barely anybody uses Chrome OS. And then there's the next embarrassing little tidbit...