RE: Whats the best combination of SPEED and KE
Mathewsboy,
You may want to consider hanging out a bit over on the technical forum considering the nature of the last few questions that I have seen you post. This type of issue is discussed regularly.
Personally, I like speeds in the 260 to 280 fps range with at least a 400 grain arrow...preferably heavier in some cases. That normally results in KE numbers of between 65 and 75 ft. lbs. With this level of KE I can shoot expandable broadheads with confidence though I could probably get away with less KE via a lighter draw weight and go with a good exposed blade broadhead as well.
Hope this is what you were looking for.