It sort of depends on what is meant by "easiest", and also upon the conditions, the rod used etc.
But as an all-rounder in most conditions and with most popping rods, I would put a vote in for the Heru Cubera 125. A beautifully balanced little popper which is very easy to get a good chug out of.
A mention should also be given to the WCP Delambre 120 - a lure I have been using a lot recently. Incredibly easy to a big chug out of, and it moves a LOT of water for a 120 gram lure.
Going up to 150 grams and I am right with Jay - Craftbait GT3.