Do Bless Weapon, Smite, Power Attack and Power Critical stack?

[Kalendraf]

The Power Crit feat just means that you auotmatically threaten, if you hit. You still have to make an attack roll, and you still have to hit with that attack roll. If you miss, it's a wasted attempt.

I finally understand my confusion. I was interpreting the Power Crit as basically giving you an automatic 20 on the 1st roll. But as it states, you still need to roll, and if it hits, you have a threat. For some reason I wasn't grasping that 2nd part until now.

So it's not quite as powerful as I originally was seeing it, but still worth investigating. Power Critical does seem worth getting for a Paladin, and the other suggestions here have been very informative. Thanks to all who replied.