I see the Web moving in a couple of differnet but related directions. The first, as hornbeck pointed out, is the migration of the Web to the mobile on the one hand and the television on the other. I don't see mobile and TV as separate platforms for the Web however; I think they will be an extension of the Internet. You will be able to get the internet experience you want but extended to your mobile device or on your TV.

In a grander sense, we will move towards a world where there will be internet more or less everywhere you go at all times. 

The Web will probably shift to be the focus of most peoples' home entertainment as well. We see the first seeds of this happening with services like YouTube and Last.fm. Eventually, you will be able to decide what you want to see or hear, when you want it and get it delivered to whatever device is most convenient for it.

Web 3.0 should also be "smarter" than Web 2.0. You will be able to find information a lot more quickly and easily than you do today with Google and other search engines.