Wii sounds like a lot of things.
Oui - French for "Yes"
Wee - Another name for urine
Well, that's all I can think of for now, aside from "We" and all the other Nintendo hippy symbolism.
I think that Nintendo made a wrong move with this one. "Wii" is such an uninspiring name. Just think, which sounds cooler coming from the guy at the counter at GameStop: "All right, we're now selling Nintendo... REVOLUTIONS!!", or "All right, we're now selling Nintendo... WEE! Or Wees. Which sounds like Wheeze. I forget." You see? What real gamer wants to ask for a "Wii"? I mean, I get all the symbolism (sounds like we and "wheee!", the two I's mean two people together, the W stands for Wario and West and Will Smith) but it's just a poor name. It's like Microsoft: They've gotten all caught up in looking cool and innovating and whatnot that they starting sounding wierd or annoying. The only difference is that Nintendo hasn't starting yapping about lucid dreams or the ultimate mind-melding experience between you and your console into the future of the horizon, etc. At least not yet.