I was importing CDs into iTunes and noticed a few usability points about the song grid...

First I saw that all text columns and headers are aligned left.  The header text being directly in line with the column text.  The exception to this rule is fields where there are divisions such as ":" (colon) or in other grids maybe a "." (period).  In iTunes the song length field has a colon ":" to separate minutes and seconds.  This is the only field that is aligned right.  I assume the reason to be because the seconds portion is always fixed at 2 characters, where as, the minutes varies from one to two.  Aligning right, assures a nice straight line along the aligned edge.

Another thing I noticed is how sorting is indicated.  The sorted field has an arrow indicating the sort direction.  If you change fields, the arrow moves to the new field.  This seems to keep the interface from getting too cluttered with little icons and arrows... keeps it clean!