[onewhippedpuppy]

Todd, for many students your approach is a wise one. Most high-school grads go to college not knowing what they want to do with their life, only knowing that they want to go to college. However, lets say you want to be an engineer. If you take the BS route, you can easily jump straight into an engineering MS program. If it's at the same college, entry is usually a slam dunk. If you have a BA, there's a number of undergraduate pre-requisites you would have to take simply to qualify for the MS in engineering, and most engineering schools highly prefer a BS in engineering for entry. English majors don't typically take differential equations, statics, etc.

Obviously every person's situation is different, but there are cases where going from a BA to an MS requires a LOT of extra work.

As for MIT, short of getting a scholarship it's difficult to justify the extra expense. There's been a number of studies showing that for the vast majority of jobs, a degree from a prestigious school does not actually give you any edge. For fields where it is an advantage, typically the alumni network is more beneficial than the actual degree. I know for a fact that my company does not start MIT engineering grads with a BS at a higher wage than those from other schools.