Bicycle tires are similar to car tires, with the exception that treads don't make a difference for road bicycle. The softer the compound, the more grip it has, dry or wet. Softer compound is wears faster and is typically more expensive. Given that, you only have a small little contact patch keeping you glued to the asphalt moving at 40km/hr with no significant protection, I tend to go for as good of a tire as I can afford. I would sacrifice other cost in other components to get a better tire.
I've had good experiences with conti gp4000s, scwalbe ultremo