Here is something that I think will have a big play in Android and perhaps other mobile devices.
Streaming audio. Ouside of checking if Congress and the White House will be handing out any more money (I'm sure we're not part of any bailout), checking e-mails, and getting weather updates and sport scores, I've been listening to streaming audio.
This can be done with any mobile Internet device provided there is an app that streams audio. And the G1 has just that app to do it.
StreamFusion is my favorite app by far. If you have a G1, this is a must have app. It comes with about twenty or so preset stations. But because it's interfaced with Shoutcast, you'll have access to many more Internet radio stations.
I think this will be even bigger than streaming video or Youtube. A lot of mobile warriors like myself are constantly on the move: driving, jogging, or working around the house. And since we have our mobile devices like the iPhone or G1 with us at all time, it is just an source of entertainment or news.
I've been listening to NPR, FoxNews, and BBC. Now, if only someone can figure out a way to get CNN's TV audio to stream, then I'll be in heaven (CNN provides audio to their regular US broadcast).
So, if you've got a G1, this is a must have app.
Note: It also works with EDGE if you happen to venture in a bad neighborhood. By bad neighborhood, I'm strictly talking about non-3G parts of the country.