the true greatsword (made from a broken sword) scales at C iirc with STR/INT/DEX/FAITH. at high stats, it is the most powerful weapon in the game. mine does something like 600 dmg per hit. the CRS does well over 1200 with it equipped. it also counts as a divine weapon and kills skeletons. it is easily the best weapon in the game once you get your stats up. i'd recommend getting it and slowly leveling it up even if you can't use it, because by the time you are able to, it will be a beast.
if you made it with a regular sword, you get the cursed version, which only scales at D for everything, but is still very strong and can hurt ghosts.
depending on your build, a fire weapon will be the most damaging option you have until you can utilize the astoria. on a STR build, a +15 fire greataxe does around 600 damage base.
me, i'm loving my furysword. with 45 DEX and 20+ humanity, i'm almost at 400 damage base, and with the fast striking and hit > roll capability of the sword it is sooooooooooooo good. the attack animation and evade for it is easily the best in the game.
also, i've discovered the best way to troll in any game in all of history. here is the process:
a: chop off seath's tail and get moonlight greatsword. (level 1 is fine. it is a crappy weapon overall.)
b: get red orb from dark covenant
c: go to anor londo
d: stand on rafters and invade people.
e: hit R2 and watch them get knocked off, whether they block or not.
f: profit in hatemail.
if you REALLY want to be a dick, wait at the corner by the two spear throwers and knock people off as they conquer it and round the bend.
LOL.