I just use a big plastic tub, not insulated. I'll throw in some 1L ice bottles morning and switch them out in the evening. Between the extra thermal mass of the 3-4gal of water, and the cooling of the ice, the temp of the brew doesn't ramp up nearly as much. Its really important for those bigger beers because the high sugar gets the yeast cranking, and the temp can run away.
Oh and by the way, if a beer isn't right I dump rather than suffer through it.