I've found that Crescent Falchion +4 (5 if you can get a Pure Darkmoon stone), and Dragon Longsword +5 when 2 handed deal a -lot- of damage, regardless of Soul level. I'm doing SL1 challenge and these weapons are great, I've had a couple of PVP experiences and they were no doubt higher SL then me and I tore them a new one using these weapons (Falchion can break through shields that don't block magic damage, and the Longsword can aswell I think)
Basically if you want an easy -really- good Weapon, grab one of the above, or a Blessed Mace +1 and upgrade it. They are all found during the course of teh regular game.
Sticking to a low SL means you won't get huge benefit from stat scaling weapons, so a lot of those are out. If you can get a Northern Regalia with Pure black or Pure white character tendency, then thats great too.
I would personally put Endurance to 40, then put points into Vitality. Honestly from doing my SL1 game you get to appreciate that some things aren't needed, even in PVP. The two things I miss the most as a melee are extra HP to tank some hits, and Stamina to swing and roll more.
Well, a proper caster can one hit you no matter how much Vit you put at low level. Homing Soul Arrows or Firestorm can do quit job of anyone. If those spells don't finish it up, slashes from a fast Crescent or Moon weapon will finish it.
Blessed build can be ok too. I fought a good one that used a blessed mirdar +5 using Clever Rat Ring.
Northern Regalia/Demonbrandt/Soulbrandt are good too. Enchanted Meat Cleaver and DBS +5 are possible, but I still have to find someone good with those weapons at 60 ~ 80.