SimonG: I actually went back. And guess what, I've beaten Nito.
Just some general thoughts on what has been discussed.
So far two of the four Bosses are down (The dragon and Nito. Also Sif, is down). I tried the four kings and failed miserably. I've only beaten the Ceaseless Discharge yet, as Kirk is hindering my progress.
I actually used the Light spell in the catacombs, as it lasts very long. Once I knew the skeletons don't respawn, and I should stay put, Nito was actually quite easy. Luckily I NEVER have to go down there again ...
I found the scale-less dragon very easy to defeat. The bigger problem was getting his tail cut off. But putting those maneater shells infront of him was also very cheap. I always ran past them.
With the DLC I'm stuck with the Antorias/Aroias Boss. I simply don't hit hard enough. At least he is easy to reach. I probably need some summons, but I don't know which SL I should be for that.
Current SL is 67. Wielding Smough's armour with a Gargoyle helmet, +5 lighting Washing Pole and using some very strong pyromancies as backup. Also, Bow of Pharis +14 for ranged kills of minor enemies. + 5 Silver Knight Shield.
I'm currently trying to get the Chaos Blade up to +5, to when I eventually reach decent Dex stats to switch weapons.
I would say head to Lost Iziliath next then and take out Bed of Chaos, be aware there is a phantom NPC just outside the fog gate you have to kill. To get to the bed of chaos you will go through some awesome ruins guarded by Capra & Taurus Demons, there are also rock worms you need to take out and depending on which guild you are in depends on whether a shortcut opens on the right side. If not you have to fight a demon similar to the one at the asylum but a lot tougher called Demon Firesage. Then you have to kill the Centipede Demon which you can see once you enter Lost Iziliath.
There is a bridge near where the Bed of Chaos entrance is, if you work your way across you will meet Solaire there and can get the Sunlight Maggot, essentially this is the other side of the door that will open only if you are in a certain guild (shortcut to Lost Iziliath and bypasses Demon Firesage). If you are in the correct guild (sorry, can't remember which one) the door opens allowing you to kill the chaos bugs and in turn changes the Solaire story ending.
When fighting the Bed of Chaos do the right hand side first (right side facing Bed of Chaos), left side is easier to get to once the battle has started. Its actually quite easy to kill, similar in a way to the Dragon at the end of world 3 on Demons souls.