That pack is full of win. I've been seeing a lot of complaints about it lacking 'Bohemian Rhapsody' but to be fair, while it's obviously a great, classic song... I don't think it's particularly well-suited for Rock Band. Aside from the vocal part, the rest of the band would be sitting there doing nothing the majority of the song.
But Guitar Hero would overchart it so you would be playing guitar on the vocals.
"We Are the Champions" is the missing song that's puzzling.