From joystiq.com:

• "AFI - "Medicate"
• A Perfect Circle - "Judith"
• Billy Idol - "Dancing With Myself"
• Brand New - "Sowing Season (Yeah)"
• Bush - "Comedown"
• The Derek Trucks Band - "Younk Funk"
• Duran Duran - "Hungry Like The Wolf"
• Eagles Of Death Metal - "Wannabe In L.A."
• Gorillaz - "Feel Good Inc."
• Gov't Mule - "Streamline Woman"
• Grand Funk Railroad - "We're An American Band"
• Iron Maiden - "2 Minutes To Midnight"
• King Crimson - "21st Century Schizoid Man"
• No Doubt - "Ex-Girlfriend"
• Peter Frampton - "Do You Feel Like We Do? (Live)"
• Public Enemy Featuring Zakk Wylde - "Bring the Noise 20XX"
• Rush - "The Spirit Of Radio (Live)"
• Scars On Broadway - "They Say"
• Smashing Pumpkins - "Bullet With Butterfly Wings"
• Spacehog - "In The Meantime"
• Sunny Day Real Estate - "Seven"
• T. Rex - "20th Century Boy"
• Weezer - "Why Bother?"
• Wild Cherry - "Play That Funky Music"

Actually, the main article was missing a ton of confirmed tracks, so I added them (and no, I didn't use Joystiq's unofficial tracklist).  There are 70 tracks that have been announced through various sources (which wikipedia has nicely organized if you're curious).

The joystiq article this came from had the smug quote: "70 of the 85 tracks that'll come on the Guitar Hero 5 retail disc have been officially announced, and it's looking like our original complete track listing -- though still technically unofficial -- is so totally the real deal."

The only song that looks more than slightly interesting is "Spirit Of Radio" by Rush. The rest I could definitely go without playing. Also I already have a few other tracks on Rock Band either as DLC or on-disc songs.

great that means we get a broken geddy lee singing. if it had to be live i would of liked the grace under pressure version

" The only song that looks more than slightly interesting is "Spirit Of Radio" by Rush. The rest I could definitely go without playing. Also I already have a few other tracks on Rock Band either as DLC or on-disc songs. "

I love that Brand New is in a music game, but I wish they'd have chosen a better song than "Sowing Season". "Millstone", "Degausser" or "The Archer's Bows Have Broken" all would have been much better choices.