Use the traps in Sen's to do some of the dirty work for you - the dart traps, the swinging blades, the ball - they can all kill the enemies for you.
Whatever weapon you jive with is the best, as long as you keep it upgraded as far as you can (+10 by Sen's). You should've picked a fair few weapons by now, they're all good really - test out the movesets and see which you like.
Some solid choices for a first playthrough: Longsword, Halberd, (Reinforced) Club, Claymore, Rapier, Estoc, Spear, Partizan, Battle Axe. The Hand Axe that the Pyromancer starts with is also surprisingly good and fast. I'm loathed to add the Zweihander to the list but no doubt people love that thing!
I completed everything except the DLC dragon and (so far) the end boss of the game with Lightning Spear +3 and pyromancy.
The lightning spear is a dead end because it doesn't scale, but I like the weight, the move set, and the range. I've yet to find anything else that seems to work for my broken spec.
Vitality - 35
Attunement - 16
Endurance - 33
Strength - 25
Dexterity - 12
Resistance - 12
Intelligence - 15
Faith - 25
I goofed early and need STR and DEX to be switched.
I don't have the endurance to handle a heavier weapon. I don't have the dexterity to scale with a better light weapon. So I can't figure out what the hell to upgrade before I start NG+. Ugh.