"The Star Spangled Banner" is not only passe, but an inappropriate song. The rampant war imagery only serves to further portray the United States of America as a warmongering country, an image we should combat (but not with bloodshed, obvs.) Plus, the song spans two octaves, and the average American does not have that kind of range to properly sing that. I don't need to hear people's voices cracking at each baseball game I attend.
On the other hand, "Party in the USA" is upbeat, celebratory, and has some obvious dance steps like "throwing [one's] hands up", "nodding [one's] head like yeah", and "moving [one's] hips like yeah" as the lyrics indicate. Furthermore, it references American cultural staples like the Hollywood sign, LAX airport, taxi cabs, Jay-Z, Britney Spears, stilettos, Nashville, DJs, the quest for fame, and, of course, partying.
We would prefer that our country drop its depressing anthem for a happier choice like "Party in the USA". Oh, and if we could make the change before the Olympics, it would be a lot more fun to watch the athletes dancing on the podium rather than pretending to mouth "The Star Spangled Banners"'s forgetable lyrics.
It's a party in the USA!