I've not been able to get control of the Wii long enough to try the Opera browser yet. My kids been browsing with it. The test I'll use is Bloglines. I can browse Bloglines on my Blackberry pretty easily with one hand, while standing up on the train. If I can browse as easily with the Wii Remote from the couch, happy, lazy me.
Eventually Nintendo will have to come out with a wireless keyboard for anything more than casual browsing. And why shouldn't they?