1) The Beatles
2) Rolling Stones
3) Elvis
4) Velvet Underground

I'm still largely unfamiliar with the Velvets and despite liking Elvis, I'm still coming to terms with much of his catalogue. Until this year, I hadn't really delved into the Stones and they'd have been #3 but now I can genuinely say I like a lot of their stuff though I doubt they'd make my top 5 overall. The Beatles are a great combination of aggressive and "edgy" without losing sight of melody and harmony.
My actual #1 overall would be the Beach Boys who I do feel are continually underrated, probably because they were never "political" for one reason and because Mike Love is a jerk for #2.