For me these are the best:
1 - General Management
Because, by doing an MBA in General Management you will have knowledge of all other specialisations and you will be able to get a job in any of the fields. By looking at Jobs perspective, this is the best.
2 - Marketing
This is one of the most popular specialisations, some of the reasons are:
-Marketing is considered as the heart of any organisation
-It is the primary revenue generating activity and directly affects the organisation’s profits
-Offers more industry exposure
-More travel
If you like to travel and specialise in a particular domain, then Marketing is very good. It generally pays more than General Management (my opinion only).
3-Consulting
This is one the best paid specialisations. Not sure about how this is in India, but in US this is one the best specialisations to do. There are lot of very good consulting firms that pay a handsome amount for people with this specialisation.
If you google, you will get a lot of resources telling you which specialisations are the future. Also, searching for Jobs in a particular domain/field will give you an idea of how the Job market is.
Thank you.