Fav exercise

The funny answer is to say sex is everyone's favorite form of exercise (proof that we all love cardio), but you're asking about biceps and that only works for single people. Curls get the girls.

I would do alternating set of chin-ups and pull-ups. Works whole arm and multiple other body parts at same time. I am more into whole body movement exercises, like squat/deadlift/cleans

I feel I can engage my biceps the most doing preacher curls with the ezbar. YRMV