Two bands I absolutely love would be Senses Fail and Passion Pit. I found Senses Fail through Dance Dance Revolution: Hottest Party. They have gotten me through some pretty tough times in my life. If it weren't for them, I don't think I would be willing to push out of my depression like how I'm trying to do now. My boyfriend introduced me to Passion Pit, whom he found through the Little Big Planet 2 trailor. They have given me faith in my relationships with my family, friends, and boyfriend.
Senses Fail and Passion Pit have proven to be a big help in my life. <3
My favorite is probably Rush, mostly because no other rock group has what I would say is probably the best bassist or the best drummer who on tours could at one time bust out a nine minute drum solo leading up to a Jazz number.
Runner up is definitely The Beatles especially their Albums after Revolver, with emphasis on Albums such as Sgt. Pepper's Lonely Hearts Club Band, The White Album,Abbey Road etc. It was in those albums you can hear the apotheosis of The Beatles, from a Scouse Boy Band into an Internationally Adored Legend.
Earth, Wind, and Fire. No band can match them in my mind. "Devotion", "Fantasy", "Shining Star", "Let's Groove", etc. They just had so many amazing songs release one after another. Would've loved to see them live in their prime.