The five familes of New York are still around, though the last ten years haven't been kind. The Gambino family, once the most visible and arguably the most powerful, has still never recovered from the imprisonment of John Gotti in 1991. His son was named defacto boss afterwards, but now I think Junior's in the joint too, and I read his skills as a boss left something to be desired. At any rate, I've read John Senior doesn't have long on this Earth, suffering from terminal cancer.
The Genovese family apparently still retains much of its' power. They were always as big and as powerful as the Gambinos, but their boss, the cagey Vincent 'The Chin' Gigante, despised the attention that Gotti seemed to crave. While the Feds tried to figure out whether Chin was wacko (he strolled around Greewich Village New York in bathrobe and a slippers, mumbling to himself), he built a tightly operating ship that kept its' mouth shut way better than the Gotti operation. In the 90s, the Mob moved into new venues like pre-paid phone card scams and especially stock 'shorting' scams.
Much of the non - New York Mafia is decimated. Cleveland was once a powerful Mafia capital, but the active membership there is down under a half dozen or so, according to what I've heard. Miami was always an 'open city' (no Mob family could claim exclusivity there, though the 60s and 70s saw Santos Trafficante as the lord of the town). 80s coke wars and 90s latin influence wrenched much of the organized crime element from Italian control.
Strange...ten years ago Gotti predicted we'd miss guys like him....that at least the 'American' Mafia had honor and rules....I suppose that could be very EASILY debated but remember this...in World War 2, the Mafia were the unofficial 'guardians' of the docks of this country's major ports. They worked covertly..and sometimes not so covertly...with police and military security people to report infiltrators, spys, sabotuers. And later, in the 50s and 60s the Mob was used as 'muscle' by the FBI..(in a famous case, a Mob hit man was flown by the FBI into Philadelphia, Mississippi and held a razor to the scrotum of the town's mayor....who immeadiately coughed up the location of the bodies of three murdered civil rights activists.)
It would be interesting to surmise what role the Mafia would play in the war against terrorists.