There is one thing that the Opera Browser makes me miss a lot.  A nifty little program Firefox has called AdBlock Plus.  Whether you hate ads because they are disturbing or simply because you despise their mere existance, I'm sure many people who have used AdBlock would agree that it's awesome and wouldn't feel the same about the internet without it.

While I admire Nintendo trying to implement a browser on the Wii (something which hasn't been done on the 360 yet), it has yet to replace PC browsers, in my opinion (at least an AdBlock infused Firefox).