It is worth noting that throughout the next 4 weeks, these are my preferences - not necessarily the generic fitness preferences.
#1 - Pull Up
Best compound for back width, it is a great test of upper body strength
#2 - Bent Over Row
Numerous versions exist, add thickness and strength to the back with a row movement.
#3 - Chest Supported Row
A harder version to the conventional row as you can't use the lower back to help you throughout the movement - this exercise really isolates the back.
#4 - Lat Pulldown
Working towards pull ups, the lat pulldown is great starting point.
#5 - Inverted Row
Amazing exercise which should be tried more often, flatter your body - the harder the exercise.
Be your best!