If Nintendo want to meet their fiscal projections of selling X number of Wiis I think it is a good idea to cut the price of the Wii. I also think with the PS3 soon to be just $50 above Wii's price tag I think it's going to take away a lot from Wii sales. And if the 360 price cut rumor turns out to be true I can see the Wii losing a lot of the marketshare at the end of the year.
Nintendo should bundle the Wii with a motion plus and Wii Sports Resort and perhaps some other game to increase its value. They can also introduce several different colors to make it more appealing
Nintendo shouldn't get too greedy and wait until next year to cut the price - get as many Wiis out there. The sooner the better for it will bring more third party love to the console.