USC wins shit.   
  
Honestly, it really depends what you're into.   
The North End is all about the Italian culture, the wharf and Faneuil Hall marketplace. 
Southie is where all the drunken Irish live and/or fight. 
Fenway is worth checking out, as is Cambridge/Harvard.  Copley, the Prudential and downtown are decent for shopping/walking around. 
If you're trying to do more tourist-like things, this city loves to stroke itself for it's importance in American history so walk the Freedom Trail, visit the State House, etc.   
Best bars/clubs are around Fenway and in the Quincy Market/Downtown area.