Jump forward or backwards in iTunes
Maybe this is common knowledge, but I had never heard of it. I found out by accident that the key combos Command+Option+Right Arrow and Command+Option+Left Arrow will jump forwards or backwards in the currently playing item, respectively, by five seconds. This is the same key combo that VLC uses to jump forwards and backwards.
[crarko adds: I tested this, and it works as described. This shortcut does not seem to be mentioned in Apple's list of shortcuts for iTunes. It didn't work in QuickTime Player or Quick Look, though.]
Source: http://feeds.macosxhints.com/click.phdo?i=2d3a456e2d70e3c0f4f98c59eaabff4e