80m or so
Reason:
The majority of Nintendo's fanbase will migrate over being the only platform now (I ain't trying to hear any of that but but they said this malarkey they said similar things with the DS) with the entire library on one platform, being the only portable system as well we should see some Vita owners migrate over as well and some new gamers may be brought into the userbase as well.
With Pokemon on the way NS is going to get a massive boost.