I totally agree with Funnytiger. Most MBAs have years' working experiences before their MBA degree so your future is determined by your working history, to some degree. It is hard to think that an employer recruits a MBA without relevant experience since the MBA should be at least in the senior or management positions. Even if you have such luck, you can't succeed in the position due to many reasons.
Anyway, some information about the placement and concertrations. Those major in Finance may earn the most if you can find a job in Wall Street. Those Management Consulting may also have the same or a bit less.
In addition to those majors, those major in management and with great experiences may find a senior management positions with good pay. In my mind, there are no big differences for other majors.
By the way, if you don't suit your major, a big suffering!