In conclusion, I reiterate my contention that New York represents the best sports city. While not my personal favorite by any stretch of the imagination (as that would clearly be Boston), New York City has to be seen as the Mecca of professional sports. There are a number of reasons why I feel this way, reasons that quite simply do not apply to any other city.
The sheer size of New York City alone gives them a decided edge. The highest population in the country by default means more sports fans. More global awareness and appeal means more popularity beyond the confines of the city, bringing a plethora of fans from elsewhere with it. The passion of the fans is a big deciding factor in the determination of the best sports city. I see just as much passion amongst the New York fan base as I do anywhere else, just in greater numbers. There is no one going to convince me that the Yankees do not inspire more passion in its vast fan base than the Tigers do, or that the Giants do not generate more emotion on a greater scale than the hapless Lions achieve.
New York city houses seven franchises in the four major North American sports leagues. That includes both leagues in MLB, both conferences in the NFL, two teams with rich heritages in the NHL, and an NBA team that may be lacklustre at times, but brings out the fans, star-studded and otherwise, to a significant degree. No other city can make this claim. This does not result in less loyalty amongst the fans for the city. At most it slightly dilutes it within the same city, but even a fan base diluted amongst two franchises in the same city (which I am not conceding) still results in the same claim to fame for the city as a whole, as the top sports city.
Rivalries can be argued to the nth degree, but they definitely are a significant component of the question at hand. Yankees/Red Sox. Jets/Steelers/Patriots. Giants/Cowboys/Redskins/Eagles. All cities can claim significant rivalries, and New York's are right up there with anyone else.
Championships have been held by pretty much all of the New York teams. The Yankees being the most obvious and impressive, but the Giants, Jets, Rangers, Islanders, and Mets have all held the top prizes in their respective sports. Even when not at the absolute pinnacle, New York teams are always in the mix.
Let's not bring the recession and the financial woes of any cities into the discussion. This has been a global phenomenon and has affected all cities to a significant degree. Even if I concede that Detroit has been hit harder than other cities, I still see this point as largely irrelevant to this discussion as a whole.
There is no shortage of excellent sports cities. New York, Boston, Chicago, and Pittsburgh have all been referenced in this thread. Philadelphia, Los Angeles, Dallas, there are lots of other cities as well who could claim to be a big time sports city. Simple fact of the matter is, though, there's only one New York City. And it is undoubtedly the best sports city out there, as much as it pains me to admit it.