i use a riggers belt. thicker belts, or any belt as close to the thickness of your holster loops i think is a good idea. it keeps the holster more secure. gun belts tend to be made ofwide, strong leather and better support the weight of the gun and ammo.
the advantage of a normal belt is not having to buy a gun belt, they can be pretty damn pricey. riggers belts start at about $5 and are a good medium between the two.