Sign me up. I play Rock Band pretty much any time I have free time.
Ideally, I'm a bassist/vocalist (simultaneously) that plays on Expert. Although, sometimes out of necessity I'm forced to play guitar. I play guitar mostly on expert. I play drums recreationally (read: I'm not very good at them) on Hard.
I am a major DLC purchaser, and I like to think that I have pretty solid, yet eclectic music tastes (I have everything from Disturbed to Roy Orbison to Kelly Clarkson). I'm fairly open-minded musically, so I'd be interested in hearing/playing pretty much anything brought to the RBN. I've also been keeping a close eye on who/what is coming to the RBN, so I'd be very excited to try some of the tracks out ahead of time.
My XBL gamertag is Fear The Cub.