My wife and I bought Rock Band 2 when it came out back in November and it's immediately become our go-to video game. Not only does it have a massive variety of songs, but it's involving and allows everybody in the group to embrace their inner rock god. I was a Guitar Hero fan before this, but I can see why they moved to bands, because it's a lot funner (even if I can't play the drums worth a darn). At any rate, even with over 500 songs available, I think that there are some glaring omissions that I'd love to see a combination of the actual bands and Harmonix fix. This really is genius - you spend 150 bucks on the game + peripherals, then you spend a bunch more on music.
Glaring omission 1: U2. There isn't another guitarist out there who I'd rather fake play than the Edge. I think that U2 should get on the Rock Bandwagon, especially with the imminent release of No Line on the Horizion. They're a band who is constantly on the edge of pop culture, and for them to not be in Rock Band is incredible to me. I don't know if the hold up is the band or the game, but we need some U2 in there.
Glaring omission 2: Led Zepplin. Stairway to Heaven would be epic, as would a bunch of other Zep songs, but Page/Plant are notoriously tight with their masters, so I wouldn't expect this anytime soon.
Glaring omission 3: The Rolling Stones. They have "Gimme Shelter" that you can import from Rock Band, but for one of the greatest rock bands ever, they need more songs. What about "Paint it Black," "Sympathy for the Devil," and "You Can't Always Get What You Want"?
Glaring omission 4: Def Leppard. These guys were huge, for good reason. They were awesome. I'd love to see some of their hits in Rock Band. I'd love it even more if you had to drum one armed while playing them.
Glaring omission 5: Bon Jovi. They have 2 songs (admittedly, 2 of their best) already, but I want to see at least a 6 pack. That is Rock Band gold. There isn't a man, woman, or child alive today who doesn't want to play more Bon Jovi songs in Rock Band.
Glaring omission 6: Van Halen. This is something that I don't see getting rectified, as I've heard that VH has an exclusive deal with Guitar Hero. Nevertheless, I'd love to see them in here.
Glaring omission 7: The Eagles. They have the most successful album of all time, and they're not in Rock Band? For shame. I'd like to put in my plug for using masters from their Hell Freezes Over album, as that bad boy is amazing.