I love Evanescence... I find their music so beautiful and I saw them live and they were actually flawless. Been a big fan since I first heard Bring Me to Life all those years ago, and they are still my favourite band today. Love their new album.
I had to define what is rock and roll once in my music class a few semesters ago in college. it is not something you can easily define, but I'm going to put my education aside and answer your question.
I would have to say my favorite band is NOFX I've been listening to them for years and I still don't get tired of them.