I for one always have the radiator checked as a rule. Water pump and thermostat is always on my list. Although not mandatory I want to make sure that the cooling system is 100%. One other thing to look at is the heater hoses as they a a B*^@h to replace when its all back together.
Basically its a excellent time to look over everything in general as you will have about 70%of the motor down.
Hopefully you dont have a milkshake in the oilpan, if so you may want to look at the the bearings.
S