I'm mostly using a +10 Butcher Knife. Has the moveset of an axe, its weapon art regenerates health on hit (how very, very Bloodborne), it has S scaling on strength, and it can be had before you're even done with the Undead Settlement. I mostly use it for bosses because mistiming a swing isn't an immediate death sentence like it would be with something like an Ultra Greatsword.
I'm also using a longsword infused with fire on a select few occasions (there are enemies in the game which fire incapacitates completely)
Other than that I'm really liking my Profaned Greatsword. It's an Ultra Greatsword which catches on fire if you charge your R2 attacks or use weapon arts. Like all of the really heavy weapons it's very well suited for taking on dangerous regular enemies due to its poise breaking capablities. Too slow for most bosses, though. It's a quality weapon with a C on both Strength and Dex, and it already hits like a truck despite my character barely exceeding its minimum requirement for Dex.
And the standard lonsword is indeed great. Fantastic moveset. Don't know which infusion it is, but there's one that increases both its dex and strength scaling attributes to a B each. That's really the thing with the From games. Sticking with the weapon you enjoy, no matter how early in the game you found it, tends to be a perfectly viable way to finish the game.