Are there multiple endings to Dark Souls?

There are two, and they are determined by a choice you have to make following the final boss fight.

You don't need to become a Darkwraith or form a "pact" with Frampt (you dont even need him to place the lordvessel, you can just jump down the hole and warp out),

The ending is only based upon walking away or lighting the bonfire. As to which ending is better: walking away is basically destroying the gods powers and the humans takeover. Lighting the bonfire kills your character until NG+, NG++, etc.

The walk away ending is better for the humans as they become well, kind of like gods, but lighting the bonfire keeps the gods alive and ruling.