A year after he announced he was quitting New York because of high taxes on the wealthy, conservative talk radio blowhard Rush Limbaugh has put his Fifth Avenue penthouse on the market. According to the Post's Jennifer Gould Keil, the portly pill-popper laid out $5 million for the 4,661-square-foot, 10-room spread at 1049 Fifth Avenue. How did he sneak by one of those publicity-shy Gold Coast co-op boards? He didn't, it's a condo. Limbaugh is seeking $13.9 million for the park-overlooking pad (which also includes a small staff apartment), so the city he despises has at least done wonders for his property value. And about those interiors, which include hand-painted murals by artist Richard Smith: Let's just say that Limbaugh's love of Palm Beach might not translate so well this far north. He knows the Gold Coast isn't actually on the ocean, right?