The short answer: nothing.
"Easter" is named after and ancient Saxon goddess Eostre (alternately spelled "Eastre"). Eostre is the mother of all things (carried into modern culture as "Mother Nature") and fertility. The rabbit and eggs are pretty blatant fertility symbols. Chocolate is a latter addition, but not a surprising one. Chocolate consumption illicits a chemical respone in the brain that is very similar to what happens during infatuation. Bunnies, eggs, and chocolate are about sex, fertility and love. What we have is a holiday this is half a pagan fertility festival and half about the Christian ressurection.