Hitomimay,
I think Andsowego's point raises an important factor in your decision.
Two other things (at least) seem pertinent:
The first is, USC accepted you at the doctoral level, while Stanford didn't. That Stanford deferred
you doesn't necessarily say anything about how they feel about your potential. After all, they're a
ridiculously competitive institution. However, it seems to me that an acceptance from a still highly-
ranked institution should count for something. Additionally, if I recall correctly, USC interviewed
you several (?) times and seems pretty intent on bringing you in. I'm convinced that being wanted at
this level is actually quite valuable...
Second, USC has apparently offered you a pretty good financial package. I can't speak to Stanford's
Masters program, but do you anticipate funding from them? I'm all for getting paid to learn...
Ultimately, I don't think I have enough information about your situation/goals to give you really good
advice, but given what I do know -- and if I was in a similar situation -- I would go to the place that
seems to really dig me. I can't speak to the issue of value of institution name, but a free doctorate
sure isn't a bad thing to have... If USC would support you at the doctoral level, it seems you would
come out a better job candidate (again, presuming you're not aiming for academia -- if you are, I say
full Ph.D. steam ahead!) because of experience (and a higher level degree), not because of 14 spots
on a not unimportant, but still rather arbitrary (and always subject to change) ranking.
Good luck with your decision.
c.o.