Are Black Cats Lucky or Unlucky?

The night Mojo, my black cat adopted me, I was a bit concerned as she crossed our path, but then an English friend told me they believe over there that they are lucky. I did a bit of research, and found some really cool old postcards with black cats, wishing people luck. I believe they are English. I've posted one here. I've also used the image of this cat and others on t-shirts and other items in my Cafepress Store. There's a link on the side bar if you want to look.

Any ways, here in the states, as far as I know, black cats are suppose to be unlucky if they cross your paths.

But, since she has come to live with us we have gotten notices of two class actions, that we qualify for. They won't amount to much, but we've never had that happen before.
So I was wondering if anyone had any stories of getting lucky or unlucky with black cats. What do you believe?

I will do some more research, and if I find any cool sites, I'll post a link to them on the side bar.