Blade types for dry cutting pavers, diamond or composite?
Diamond blades aren't that expensive and cut much more quickly. They're much thinner, for one thing. I wouldn't use anything else. 

However, doing so with a circular saw won't gain you much. Maneuverability is poor, meaning you're stuck cutting through the material in a big bite. A 7" angle grinder is the ticket. You can slide it back and forth and cut with much more control.