For rifle it would have to be W-748. I load everything from .223 up to .30-06 with very good results. IMR-3031 for the .45-70 is the second rifle powder.
For handgun it is W-231. .32ACP up to .45 acp. Acceptable results in all. The only other handgun powder I use is W-296 for magnums.
Since this is I THINK? a blackpowder forum section, if you are talking about blackpowder and substitutes, I have used most of them from GOEX blackpowder (hard to get in my area now) to Clear Shot, American Pioneer Pwdr, Triple 777, and Pyrodex pellets, Pyrodex RS and Pyrodex Select.
Overall, I have had my best accuracy and consistency using the Pyrodex Power and pellets. I like the older Winchester 209 primers and since i don't often use triple 777, I have no issues with the "Crud Ring" situation using hotter primers. I also like the Reminton Kleen Bore primers over the Triple 777 primers. Some guys do not like them, however they have served me well and never had a misfire.
I currently hunt with either 110 grain Pyrodex RS behind a saboted 250 grain Shockwave out of an Encore 209/50. I am getting 1/2 inch groups at 100 yards with this and set exactly 2 inches high, I am dead on at 150 yards. I am not a big fan of 200 yard shots with a ML. I also own a TC Omega and obtain similar results.
If I need to make a 200 yard shot, one normally has more time to set up for that and with a range finder and a good steady rest, it can be done. I am more concerned about threading the needle at 75 yards through an opening at the vitals in the brish etc. The 1/2 inch groups at 75 or 100 yards are more important to me than the drop at 200 yards.
Too much emphasis in my opinon on turning your in line smokepole into a 200 yard rifle. most der are still taken at less than 100 yards.