For myself, it's the Falchion. I never gave it a second look the first time I picked it up, but it's steadily becoming one of my favourites. --- "Sad... so sad. A host of sorrows... and you are one of them." - The Sorrow, MGS3.
PvE: Longsword - does everything you need and quick; tad low on the damage but the versatility is great
PvP: going from word of mouth* I have heard good things about the Barbed Sword from Photos, I like the Garg Axe (reach and some decent stunlocking), and the Flamberge just doesn't get enough love. --- If you build your shop in front of an arrow trap, sometimes you are going to get shot by an arrow.