It's a toss up. If it were 2007, both would give you a reasonable shot at a Wall Street gig. Those days are long gone.
UNC will plug you into Charlotte/Southeast financial scene. It's also has stronger ties with the Northeast because of an east coast alumni base. Vanderbilt isn't really a Wall Street feeder. Even for MSF and MBA, it places more into corporate finance roles.
Outside of finance, UNC is closer to the RTP, which is a more diversified economy than Nashville. UNC will also put you closer to DC.
Neither are really ideal for returning to NYC after graduation. Geography hurts you in the both cases. Personally, I would look more at local northeast universities, if it's not too late. If that isn't doable, then I would go to UNC, get straight A's, then immediately apply into a highly-ranked MSF program -- MIT, Princeton, etc.