What do you think the best power/drivability combo is?

Just look at what the new car manufacturers are doing for your answer; going back to smaller engines with fuel injection and turbocharging to make up for the losses. Modern diesel engines also show this to be true.
Everyone understands that moving air and supplying fuel makes power, no matter how you get there.
I like the simplicity of naturally aspirated engines, but I have been itching to do a boosted build for a street strip car. Going to be a while for me.
Once plumbed properly, and if the riggt parts are chosen, and if not too greedy with timing, a boosted small block should live a long happy life in the six hundred horsepower range.