I guess it's impossible to say this is the all-time best band.
My the most favourite is Jethro Tull but I don't want to forget about Pink Floyd , Rolling Stones , THe Cure , U2 , Fairport Convention , Police , Sex Pistols , Dire Straits , Placebo , Black Sabbath , Uriah heep , Faithless , Peter Gabriel band ,
THe best rocker of all ages is probably Ludwig van Beethowen - just imagine what songs he would write if he had an electric quitar
What I don't like is music of The beatles - but I respect that they are probably the most respected music group of all time for lots of people