Enemas definitely work best for me. I find glycerine suppositories largely ineffective, and the dulcolax suppositories seem to do a better job of creating a strong burning sensation than they do of cleaning me out. I do, on occasion, take laxatives, and they will clean me out, but taking laxatives at bedtime basically forces me to keep the next morning and early afternoon free. When I go the laxative route, I generally end up finishing with a couple rinse enemas.
As far as enemas go, two quarts of soap suds or water with some lemon juice mixed in will do wonders for cleaning me out. I'm expelling two quarts of soap suds right now, and after a good rinse or two, I'll be good to go.