So my question is; outside of the basic gear (helmet, gloves, boots) what is a must have and what is an overkill?
I try wear as much protection as I can. You could be the best rider in the world and the risk is still there from cars, trucks, weather, etc. I believe in ATGATT.
I wear:
Full face helmet
Riding gloves (gaunlet-style mostly)
Motorcycle jacket with armor (shoulder, spine, elbows)
Motorcycle overpants with armor for hips and knees
Appropriate boots (with a hard toe) that lace above the ankle
It slows me down a bit to put the gear on, but I have more fun riding when I feel safer.