I couldnt imagine naming just one! Tool, led zeppelin, nirvana, weezer, the beetles, rush...and f*ck it , i love blues, progressive jazz and progressive rock. Dream theater for the insane drum and guitar parts and jazz mandolin project for the same thing. There are too many dimentions to music to just pick one band or even just one genre.
totally agree its like saying whats the greatest beer. I could never name just one. not to mention the best style.