As fun & useful as it is to get all hand-wavey about big design issues (design thinking! innovation! stop designing products! soylent green is people!), sometimes it’s equally fun & useful to take a good hard look at just one design element.

• History of the Button – "Tracing the history of interaction design through the history of the button, from flashlights to websites and beyond." (thanks Phil!)
• The dashed line in use – "Even though the dashed line has emerged from a designer’s shorthand and
  from the limitations of monotone printing techniques, it has a clear
  and simple visual magic, the ability to express something three- or
  four-dimensional in two dimensions."
• And an oldie but a goodie from Luke: The History of Amazon’s Tab Navigation. Long live the uber-tab.