If -- IF -- the US price is $300, I'll have to wait until a price drop. I realize it's probably worth the price, but the general public isn't going to think about that. They'll just see a new handheld system, then see the price. It's what killed the PSP Go (well, that and crappy support).
My guess is $250 for North America. Any higher, then - and I admit I'm no consumer analyst - I think it'll hurt Nintendo a bit.