Second the halyard wrap preventer.
I also love the Harken rachet block, in the cockpit at the end of the furling line. It makes it much easier to deploy the jib in a controlled manner (like if you want to deploy it partly furled, and it's windy), and the steady tension on the line makes the line wrap nicely around the drum.
Harken 57 mm Carbo Ratchet Block
It works best at the aft end of the cockpit, so the line does a 180 degree turn around it, then back to the cleat.