I like to do the Devin Townsend delay thing. I'm not sure if he really does it, but it sounds so much like his style that I go ahead and credit it to him anyway. You may have already tried it, but its where you pan a dry signal to one side and a slightly delayed (like 8-15 milliseconds or so) to the other, and it acts as a simple doubler. The only problem is that now your vocals are panned to the sides as opposed to straight down the middle, which can make things a bit trickier mix wise, and listening in mono will destroy the effect, but it sounds friggin rad when all goes well.