I bought Dark Souls because my ex girlfriend wanted to see me play it, "I want to see you die!" she said when I told her about it. I beat the Taurus Demon (I believe he's called that anyway) and damn, I thought he was tough, after that I stopped playing and didn't pick it back up until last month I think (with a new character) and I love it. I bought Demon Souls after Dark Souls, but I got so mad at the mines, haha.
But as you said, being able to play with friends would be great, I really hope you're able to do it more easily in Dark Souls 2, I've heard something about voice chat too, but I don't know if it's in, would be great though.
What Pravado said is kinda useful, if its like that in DkS 2 at least, didn't know that Dks 1 had been made "easier", and damn, Was Ornstein & Smaugh (don't know how to spell the names) harder before?!