I'm surprised nobody brought up the AC/DC track pack for Rock Band 2 yet.
http://kotaku.com/5056832/rock-bands-acdc-live-track-pack-+-the-detailsThe long and short of it is that it's releasing on the 2nd of November for the 360, PS3, and PS2. It releases on the 16th of November for the Wii. It will only be sold at Wal-Mart and will carry a retail price of $39.99 for all systems except the PS2 which will be $29.99. The PS3 and 360 versions will include a code that lets one transfer the music onto your harddrive one time only. That will help avoid any disc swapping. All the songs will be masters from live performances. Here's the 18 song track list:
"Thunderstruck"
"Shoot to Thrill"
"Back in Black"
"Hell Ain't a Bad Place to Be"
"Heatseeker"
"Fire Your Guns"
"Jailbreak"
"The Jack"
"Dirty Deeds Done Dirt Cheap"
"Moneytalks"
"Hells Bells"
"High Voltage"
"Whole Lotta Rosie"
"You Shook Me All Night Long"
"T.N.T."
"Let There Be Rockâ€
"Highway To Hellâ€
"For Those About to Rock (We Salute You)â€
I'm a huge AC/DC whore so my opinion is going to be understandably skewed, but almost all of those songs minus three or so, are the absolute best songs they did. Furthermore, 18 songs for $40 works out to be a bit over $2 a song, which is the standard for DLC. All in all, even if I hadn't had RB2 already, this would have been the straw that broke the camels back, so to speak. Hopefully, the Wii RB2 owners will get some way to transfer music to SD cards sometime next year.