Expand or Shrink All Details in Get Info Windows with an Option Click
If you want quickly expand (or minimize) all of the detail sections within a Get Info window, just Option-click a single arrow. Instead of only expanding (or shrinking) that subheader section, all detailed sections will expand or shrink concurrently.
This may be an addition to OS X Lion only, at the least I didn’t know about it before Lion existed.
Update: Apparently it works in Mac OS X 10.6 and earlier as well, thanks to those who pointed this out in the comments.
Update 2: For those unfamiliar with “Get Info” windows, select any item in the Finder and hit Command+i or choose “Get Info” from the file menu. The resulting menu gives you details on the file or application, the ability to change permissions, file type, and more.