This won’t affect the majority of the Wii U’s potential owners, but it’s been confirmed (via Famitsu magazine) that the next Nintendo console won’t be region-free.
“What can be played on the Wii U is restricted by a region-lock feature;” is the offered up translation from Japanese. “Software not sold in the same region cannot be played.”
In other words, the Wii U is region locked. Buy it in Europe, and it’ll only play European games.
This shouldn’t be a massive surprise – the Wii was region locked and the DSi and 3DS suffered the same fate – frustratingly for handhelds.