"good riddance"

As far as I know, that's an abbreviation of "good riddance to bad rubbish" which means you are pleased that someone bad or something of poor quality has gone/is going.

One site I found http://www.geocities.com/PicketFence/7608/sayG.htm attributed it to Charles Dickens (1848) Dombey and Son - I'm not sure of the accuracy.

That's about all I've been able to find though. Oh, except there's a reference to it on a site called dumpaguy.com - can't imagine why?