One of my biggest Mac annoyances is that whenever I turn up the volume, each step is so big that I can't always get the volume right where I want it. This hidden shortcut lets you adjust the volume in smaller increments.
This shortcut has actually been around for awhile, but it disappeared in Mac OS 10.7 Lion without explanation. If, like me, you were extremely disappointed by its disappearance, you can rejoice, because weblog Mac OS X Hints has discovered that it's back in 10.7.4.
To adjust the volume in smaller increments, just hold Option+Shift and adjust the volume with the volume keys as normal. You should find that it jumps up and down in quarter notches instead. This also works for screen brightness, incidentally. And, if you just hold Shift while adjusting the volume, you can raise the volume without the annoying "pop" noises.
Shift-Option Modifier for Volume Control Returns in 10.7.4 [Mac OS X Hints]