Home heating fuel comparison (wood and heat pumps)
You're right, but only because oil is the worst, most expensive way to heat a home. Pretty much anything beats it, except maybe electric resistance in places with high electricity prices. Wood, gas, and heat pump electric will all beat the pants off oil. That said, even 80% efficiency may be optimistic for a modern high efficiency wood stove. But even if that's overstated, as you can see, it's still a pretty good deal.

Additionally, your calculations may even be understating the advantages of a heat pump. 1.4 as the coefficient of performance is very conservative. I'd use 2, especially given how they not have high-efficiency units on the market than can deliver their rated performance at -15f. Some can go as high as 3 or 4 during periods of non-frigid outdoor temperatures and less than peak internal load.

Edit: you said, "Does that calculation make sense? Are heat pumps and wood inserts really that much better than oil? Can I really save 178 dollars a month by going with a 16 SEER heat pump?"

Yes indeed. But again, only because oil is such an awful fuel. Anywhere in the USA, one therm of oil heat is several times four times as expensive as one therm of natural gas heat, simply because of the relatives prices of oil vs natural gas. If you were comparing a wood stove and an electric heap pump to natural gas, it would get a whole lot more complicated--especially in the cases of a 95% efficient gas furnace, or a state with low gas prices or high electric prices.

No matter what you choose, do your wallet and the planet a favor and heat with something other than oil! It's expensive, it's dirty, and (IMHO) it contributes to awful foreign policy. Just Say No!

Edit 2: Some gov't verification of your numbers: http://www.eia.doe.gov/neic/experts/heatcalc.xls