if the original poster is interested in security studies programs in EU, he/she should absolutely consider the London King's College War Studies Department
I think Columbia and MIT are by far the two top places for Security/IR.
Columbia has a wider faculty, and probably its average level is higher than MIT's. MIT seems to have a program focusing more on technical aspects of military operations than CU's.
I would not recommend JH (in the sense of SAIS) for a career in academia. Much better for policy (but you have to be happy dealing with some neo-cons)