The average cigarette has ONE mg of nicotine. They range from .6 to 1.4 or so.
In general I think the following levels are ones various smokers should try (and try other levels as well)
full strength smoker - 24mg
lights smoker - 16-18mg
ultralights smoker - 10-12mg
I think those feel similar in TH to the various cigarette type. but it also depends on your equipment, your juice's PG/VG, and how it feels to you