The top song list on RBDLC seems to skew towards harder difficulty songs and the reviews are mostly based on how fun they are to play on expert difficulty, without much regard to how good the songs actually are to listen to.
Here’s the recommendation list I posted a few weeks ago.
Mother Hips - Red Tandy: One of the best drums and bass songs in the game. Guitar is pretty entertaining. Ends with a long jam that will bore the vocalist to death unless he/she is also playing an instrument.
The Who - Who Are You: fun song for most instruments, but the bassist will be bored. It’s ranked as one of the hardest drum songs of the Who pack, but I think it’s a little overtiered on expert, so perhaps beware on lower difficulties.
The Who - Going Mobile: Tough drums on expert. I’d put this higher than Who Are You at least for expert drums, so maybe a bit easier on lower difficulties. Guitar is enjoyable and challenging.
The Who - My Generation: Drums are fast and a bit tiring on this one, but the bass and guitar are both a lot of fun. A classic song, might as well grab it.
Black Tide - Shockwave: There aren’t too many guitar charts in all of Rock Band that are charted in a way that make me feel like I’m playing GH2. This is one of them. Challenging, but not impossibly frustrating, speaking for myself at least. I like the drums in this one as well.
Judas Priest - Electric Eye or Bloodstone: Might as well get a Priest song or two, but I wouldn’t recommend the whole album. Electric Eye is fun on guitar and a kickass song overall, but kind of repetitive on drums. Bloodstone is fun for me on both guitar and drums, but not as good a song.
Radiohead - My Iron Lung: Just a great song. A bit on the easy side for me on most instruments, but my friends love playing it (many of whom were not even previously familiar with it).
On top of those I’d recommend:
pretty much all of the Boston songs
the other Who songs
The Killers - Spaceman and Mr Brightside
the Black Sabbath songs
Rush - Working Man, Limelight, Red Barchetta
The Cars - Just What I Needed, My Best Friends Girl
Grateful Dead - Casey Jones, China Cat
System of a Down - Toxicity