Personally, the best picture I took was with the 43. But it is a difficult lens for me. Perhaps 7 or 8 out of 10 ends up in a trash bin. I find it difficult, but every now and then, I nail a shot that's worth every penny I paid for it. It probably means I'm not working hard enough.
The 77 is just pure effortless magic. I like it (a lot) but I also feel that there's still much to learn. I have a higher keeper rate here, but at this moment, I'm still using it as a one-trick pony: (stop down, portrait shoulder up, and admire that film-like rendering). I guess that this should be more versatile with more practice.
Ah, the 31. If you look in a dictionary for the definition of "pixie dust", you'll find a lovely image of FA31. Enough said.
As to your choice, I believe it should not be a question of "or" but "which one to get first". If I were to do it all over again, I would have gotten them in this order 31-77-43, instead of the 77-43-31. Given your options, I'll vote for 77, then 43.
But hurry before the FF comes out and the prices double