Most of the words offered in this thread so far are what I would describe as dialect or interesting local terms, but are not really slang.

The words in Sandman's list are what I would call slang. They have an element of dislike or insult, and are not necessarily restricted to one area.

Another thing about slang is that it keeps changing as new terms are invented, which then spread as people hear and use them, while other expressions drop out of use.