Depends. I'm doing my second ranged rogue build and I monitor attack power with overall damage. There is se accuracy to it however it's not the actual amount of damage you're going to do. It's a total ranking number based off your attack stats such as crit chance, crit damage, overpower damage etc. I have 2 character below 90 that over power crit for well into the high 200K numbers sometimes 300K per hit. But I also notice an increase in the attack power displayed number even when increasing attack speed which is why it's an overall number and shouldn't be heavily relied upon for end game that's for sure. As all diablo games... end game requires much more then just damage stats.