Impact55: I don't know how you define rock or what type of rock you are interested in, but I urge you to check out Sublime. Even though I am devoted to hip-hop, I would definately consider Sublime one of my favorite artist(s) of all time. If you have any taste in music you will definately like this band. My favorite songs off the most popular 3 albums are:
Sublime (self-titled) - What I Got, Wrong Way, April 29, 1992 (Miami), Santeria, Falling Idols, Caress Me Down, Doin' Time
40 Oz. to Freedom - 40 Oz. to Freedom, Don't Push, Badfish, Scarlet Begonias, Ebin, Date Rape
Robbin' the Hood - Greatest-Hits, Pool Shark (acoustic) (a song about heroin and his struggle with his addiction, including foreshadowing his own death), Work That We Do, Boss D.J., Falling Idols, Freeway Time In LA County Jail
If you PM me I could hook you up with some stuff.
konichiwa: I haven't given The Ecleftic much of a listen but you must check out his first album, The Carnival, if you like this one. It is also very unique and original. However, I would like to say please don't consider Nelly to be hiphop. His music is bubble-gum pop-rap, nothing more and definately not gangsta. I'm not sure how people will take to the new Outkast, it is very experimental. Check out Aquemini or Southernplayalisticadillacmuzik (yes, that is the album title

), which I think people would like a lot more.
-mosdef