Before buying anything, make sure your bow is tuned like @Fogman77 described above. Make sure your arrows are stiff enough. I've always been able to tune a bow to shoot a stiff shaft well. After that, I highly recommend 125 gr. G5 Strikers.
Gotta love them Slick Tricks.These are the most accurate broadheads for me.
Crossbow - Sevr 2.0 100g
Compound bow - Slick Trick 100g
Stick bow - old bear heads