Wii HD
Nintendo is showing off a bit more of the Wii on their new wii.com site. And they're showing some interesting stuff.
The Wii is not being touted as a high-definition gaming box, but 
take a look at all of the screenshots and video clips they're showing. They're in a 16:9 aspect ratio.
And look at the specs for video connections:
Output: an AV Multi-output port for component, composite or S-video
So the Wii is capable of component video output. With S-video, for a non-HD picture, there is no reason to add component video: An NTSC signal isn't going to look any better over component than S-video.
And there wouldn't be any reason to use a 16:9 aspect if you're not outputting an HD mode - otherwise you're just throwing away pixels.
The ATI chipset the Wii is using for video is most likely capable of generating an 1080i or 720p signal. Most chipsets are - 720p is close to the number of pixels you get from 1280x1024, a resolution supported by every chipset made in the last 5 years.
I'm speculating that while the Wii may not use HD for gaming (due to bandwidth and memory requirements), it will use HD for menus, and web browsing.
That's a tradeoff I'd be perfectly happy with.