The best that I have found so far are mixes of TPA flavors. I like my flavors a bit light and sweet, compared to some.
6% TPA RY4 Double
4% TPA Tobacco Blend PG
+ a hint of a contrasting flavor for a pipe tobacco alike flavor
or
~.3% TPA M-Type Premium (this stuff is incredibly strong, to me)
7% TPA Tobacco Blend PG
+ a hint of something else
The Tobacco Blend is the absolute mixed with Ethyl Maltol, and is pretty sweet on it's own. I find that both the M-Type and the RY4 Double both offset the sweetness of that, and result in a nice flavor.
There are still many tobacco flavors that I have not tried, though, so I'd bet that there are better ones.
ETA - Forgot to point out that these all contain some artificial flavors, if that's a big sticking point.