Nexcare by 3M are quite good in my experience. The waterproof ones have adhesive all around the pad and do not come off or become contaminated easily. I've sweated outside working with them in the dirt and the wound stays clean and the adhesive doesn't come off very easily (except on the hairiest of spots, they stick well).

Their other styles, like padded/gel, elastic fabric, second skin, etc. have all proven to be excellent and they are cheaper than most of the other brands.