LSD is a must for me, especially on RWD vehicles.
I found that (here in Canad) open diff's are horrid, and often scary at times when trying to accelerate up a hill in heavy traffic. LSD greatly helps this, and I have over 70K on my BFG Long Trail tires with lots of wear still left. My GoodYears on my old C1500 GMC didn't last very long even with regular rotations. Each winter it was a struggle to get traction even in some parking lots with the snow/freezing rain and a mix of the two in my geographical area, and the GMC's open differential was a definite set back.
I too would avoid a locking rear diff as it can bind the axle and lock when you need the turning radius on the road. Auto lockers are more for off-roading with very little street use as they can be unpredictable. Air lockers are a viable option but they too can cause trouble if you forget to turn it off while driving on the road in dry conditions.