i second the idea about "proficient motorcycling". although i've never read it myself, i do subscribe to MCN and have read some of his articles so i'm sure it would be a good book for newer riders or maybe even long time riders as myself.
as far as you question goes though, i find myself using the rear brake more for stability and balance in low speed maneuvers such as parking lots and u-turns almost never touching the front in these conditions, especially when there is loose gravel or sand around. i sometimes will use it to scrub off a little speed and stabilize the chassis when entering high speed turns as well. i also find i use it at the very end of a stop like at a red light as it allows for a smoother stop with less chassis pitch and reduces the helmet "bonk" from my passenger. and off course there is always rapid stops where i use both together but depending on the bike this can be tricky due to weight shift and how light the rear wheel becomes. of cours this is just for street riding. when riding dirt on my ktm it is a whole new set of parameters.
"some might call it a 'midlife crisis', I prefer to call it a renaissance of thought and action"... "Life is too short to do anything other than that about which you are absolutely passionate."..."Adventure is a frame of mind, set upon by action, not defined by equipment."..."It all boils down to your ability to say "SCREW IT" and really mean it"....Randy