According to last week's Wall Street Journal, toys on Toy Wish Magazine's "Hot Dozen" list are often in scarce supply at Christmastime. (The NXT is on that "hot dozen" list).
Nevertheless, I'd be very surprised if the US faces a holiday shortage of NXTs, for three reasons:
1) Lego specialty stores in the US have been promised an adequate supply of NXTs, according to the Lego Store manager in my town.
2) A large number of "big-box" stores sell NXTs (Best Buy, Target, Toys R Us, Walmart), not to mention a slew of online retailers.
3) Stiff competition from the Nintendo Wii may increase the availability of NXTs. (The Wii will be in NXT's price range).
Still, NXT spot shortages DID occur in August of this year. (Some Amazon.com customers had to wait several weeks for their NXTs in August).
Is the NXT available where you shop in the US? How about Europe and elsewhere?