I am not a huge fan of the World of Greyhawk...just never got into some of the names that were used...didn't jive with me as a 13-14 year old. Now I love the City of Greyhawk and I am thinking of taking it as is and using it as the large city in my world, north of where the player's are now. The notes I have for my city place it near a river and a lake so I'm thinking that this would work well!
Now I have a lot of info on the city from my 1st and 2nd edition days so this should be a fun addition...now I just have to figure where I'm gonna put Waterdeep and Bard's Gate! ;)