Version:            (using KDE KDE 3.5.4)
Installed from:    Ubuntu Packages

It would be very nice to have a drop down menu at the top of the playlist that allows you to order the fields to sort by in descending order of importance with a radio button that has custom sorting, default sorting, no sorting.

The drop down box should populate itself with the fields you have displaying in the playlist.  You should be able to check or uncheck the fields that you wish to be used in the sorting.  You should be able to drag the fields in the drop down box around to determine their sort order.  The field at the top of the list will be the first sort order field.  Follow that through to the last field determining the final sort order. (Think mysql:  order by column 1, column 2, column 3 etc...)  

With custom sorting enabled, all auto sorting by album or artist or whatever should be turned off and the sorting specified in the drop down box should be enabled instead.  With default sorting enabled, sorting should occur automagically as it does now.  With no sorting, tracks should appear in the exact order they are added.  

The playlist should sort in real time as the order of fields is changed or a different sorting option is selected. 

The drop down box might look something like this (sorry for the ascii art :) ):

----------------------
+V Sort Playlist     +
----------------------
+[x]Artist+ (O)Custom+
+[x]Year  + ()Default+
+[x]Album + ()none   +
+[x]Track +          +
+[]Title  +          +
+[]Length +          +
----------------------