Mostly, I don't much care for it; the vast number of people playing Xbox live are teenagers who get bored easily and tend to, for example, quit in the middle of a song when you're playing Rock Band. I also don't really enjoy being yelled at by a 14-year-old because, since I do not spend seventy-four hours a week playing video games, I am not quite at his skill level on Call of Duty 4. Still, I've enjoyed a few sessions of Rock Band*; the interface is super-smooth, the collaborative play is fun, and it gives me my all-time favorite video game story:
One of the songs you can do is "(Don't Fear the) Reaper by Blue Öyster Cult, which I really dig, because it's got my all-time favorite guitar solo and it's fun to pretend I can play it. So I found a group on Xbox Live running through it, and you know how you can buy those headset mics to talk to people you're playing with online?
The guy playing drums in our band had an actual cowbell, and he played it during it song. We could hear it over his headset mic. After the song was over we all gave him a round of applause. I'm pretty sure this is the best use of technology ever.
*: If any of you play Rock Band online, or any other Xbox games, hit me up -- we'll run a game one of these days.