The Demon Scythe. It's amazing for tactical combat, as if you can think fast enough, you can place multiple scythes aiming in precisely the direction of where an enemy's going to be, or corner and herd people in PvP as it's hard to tell which way scythes are going to go until they start moving, and by then you have to dodge several of them, and now you're trapped, and now she's got several aiming for your head...
It's also a great makeshift melee weapon, as one blade and a quick backmovement will cause an enemy to hit the blade, not only dealing knockback, but having the blade speed into the enemy a second time, causing further knockback.
It ALSO makes an amazing tool for lighting up caves you can't see in, or splashing against walls after building up a bit of speed in order to reveal ores deeper inside.
It can also be spammed fast enough for a massive area attack, and can pierce five enemies in a row, which is insanely good crowd control.
It also does 35 damage, which with some damage boosters can easily get all the way up to 45 or 50 (my current pre-hardmode character has one that does 52, with 38% critical! Note I'm using a couple mods, but they have minimal effect)
It continues to be amazing as an awesome weapon against the Destroyer, though by then I usually have the Magical Harp, which is a wee bit too slow for my tastes to use as a normal weapon.
It probably helps that my characters tend to be very agility/damage based, and tend to have multiple movement accessories.