I'm a huge Valvoline fan. My stock motor with more than 150,000 miles on it was clean as a whistle on the inside when it was pulled.
My stroker is still very new. I'm using dinosaur oil in it still (Valvoline, of course). I'll continue to run 10W-40 in it until around 5000 miles.
After that:
I run 5W-30 in the winter and 10W-30 the rest of the year in a synthetic or synthetic blend.
The weight of the motor oil that you use will largely depend on the motor. The tolerances in my motor are on the close side so I run a pretty light weight oil. 20W-50 is pretty thick. I'd not be running that oil in newer motor unless you're in a very warm climate.