Hollywood, CA = Hollyweird
Lake Placid, NY and Saranac Lake, NY had a bit of a rivalry going - Lake Plastic and Saran Wrap Lake were their monikers for one another.
Omaha has been referred to by some as “Obamaha” ever since residents there gave one of the state’s two electoral votes to our current President in 2008. Whether that is a slam or a compliment depends on one’s political leanings.
Across the river, Council Bluffs, Iowa is often called “Counciltucky”, for perceived redneck behavior.
The truly dim-witted and ignorant sometimes refer to San Francisco by an F-word which is too filthy for me to repeat here. I strongly recommend against its use, particularly within the city limits, as there are some offenses against propriety which can still serve as a legitimate justification for homicide.
Bristol in England includes a suburb called ‘Bradley Stoke’, known locally as ‘Sadly Broke’, a fair description of the majority of the inhabitants.
And people in Lost Angels barely know San Stripmall exists. 
An attempt to establish the slogan “The City that Reads” in the early 80s was subverted by some local wags into “The City that Breeds”.
The much older unflattering moniquer “Mobtown” is used mostly by the local alternative media scene any more. OTOH the reference to natives as “Baltimorons” ***is *** still common.
Portland, OR gets called ‘Stumptown’, but usually in an affectionate way.
Castle Rock, WA, obviously, has become ‘Wrassle Cock’ locally.
Since Mt. Vernon, WA has been revealed to be the home town of Glenn Beck, it now has a real reason for its old nickname of ‘Mt. Vermin’.
India-no-place.
Yonkers has no nickname, probably because no one can think of anything more derogatory than Yonkers.
Slippery Rock - Slimey Boulder/Pebble
Swift Current, Saskatchewan = Speedy Creek
Ithaca NY = 10 square miles surrounded by reality.
Not a city, but the Florida panhandle is known as L.A.
Lower Alabama.
AKA the Redneck Riviera. And I live in what is locally known as Panama Shitty (Panama City) . I moved here from Tallanasty (Tallahassee) .
I may live in Vagina, SK, but at least it isn’t Winterpeg, MB.
Also “America’s Wang”.
we need to get some ohio cities in here. scarion and cincinasty for marion and cincinnati are obvious cuz those towns are crap. to do lee do for toledo is a little more tricky. it’s mostly because all the people are unemployed and twiddle their thumbs singing to do lee do all day everyday. little detroit and slime-a for lima. come blow us = columbus. chilli-comptons = chillicothe.
Why, I live in “Hashland”, (Ashland) myself, so named for the hordes of dirty hippies who live in the park in the summer. But it’s loads better than “Methford” (Medford), our neighbor to the north, or their sad, depressed little suburb “Quite Shitty” (White City). Grant’s Pass we usually just change the inflection.
My friend from Sacramento referred to the city as “SUCKramento” or “EXcremento.”
I’ve heard people say they are ‘living in the state of Misery’, meaning Missouri. The parts of Missouri I am familiar with are wonderful. I figured those people hadn’t discovered them yet, or were insufferable snobs.
When I was in junior high, we used to call our city Krap Room. Because that’s Moorpark backwards. We were oh so clever.