The Good: Its short, there are so many different marketing options/slogans available its ridiculous. Look at all the ones that ya'll have made. Its "modern" and "japanese-y" two things that are very big in the U.S right now, especially with gamers. The i's in Wii remind me of the iPod (and other mac devices) and you can't get any more trendy/popular than that.
The bad: In immature people (read: most guys) Wii denotes a phallus or urine depending on the context of the sentence. This WILL make people laugh at Nintendo. Can't you picture PS3/360 fanboys taunting us and telling us to go to our rooms and play with our wii's? (or something to that affect)
Overall: Definately a gutsy move on Nintendo's part. The name is sure to get them all sorts of press coverage as well as 1,000's of discussions just like this one across the internet hoping that its a month-late April Fool's joke. With the right marketing, amazing games, internet connectivity and ds networking (and the ability to poke fun at themselves) it really won't matter all that much. To the nay-sayers who say that Nintendo's days are done, look at the DS. Many people thought it was sparkling innovation-y, had worse graphics compared to the PS3/360 and more. Now its outselling the PSP by as much as 6 to 1, has good marketing, good games, wifi (and OPERA!!). Compare this to Wii vs. the rest. Same story. Worse graphics, "sparkling innovationy" and cheaper.
Nintendo is trying to repeat its DS success and is using the exact same plan and I think its going to work.
-Blueflame