I'm with chasingembers, I seem to be immune to nicotine. I predominately smoke the strongest tobaccos available: 1792, MB Bold Kentucky, Irish Flake, 5 brothers, Revor and all of the GH ropes and plugs. Even with big bowls, I detect not even a faint change in my brain chemistry, other than a feeling of satisfaction and satiation. My favourites for flavour, although not strong at all in my book, are Old Dark Fired and GLP Jacknife plug. The strongest of all, IMO, is an Indonesian tobacco called Tambolaka, but I don't think it tastes very good and is a bugger to prepare.