T-5's and T-8's.
They dont have any cold start problems- they start right up, they are cheap to run, and the bulbs outlast the old T12's.
I have halide high bays as well, just yanked six of em out of one building- the halides buzz, and are kind of weird colored light, even if you get the socalled "white" bulbs. Meanwhile, T-5's and T8's have a wide range of colors of tubes available, you can get which ever ones you like the best.
My wife is installing new T5's where those high bays were just removed, the buzz drove her crazy.
I just put a pair of T8's in my wood shop, tossed the old 8' T12's, and the light is better, they start right up, and they dont flicker.
I am doing the machine shop next, and then the fab shop.