well, this thread has to have been done a few times more than excessive.
But, I like to share my views, so:
Queens of the Stone Age - They are the one refuge I have for modern rock that I feel still have the ideals and sound of older rock. This means they aren't progressively emo, or punk, or other generic sound that this generation of music has pumped out thus far. "Mosquito song" goes down as one of my favorite all-time songs ever made.
Sam Roberts - The best canadian band imo, they continuously get better and better, and I am pumped to see them in January. They play a folk type of rock, and aren't garbage like most other candian rock ensembles (curses nickelbacks). My favorite song of theirs is "love at the end of the world"
Flogging Molly - No words for this band except that you will never find better celtic music. Each album, especially their new "Float" Album, is absolutely unreal, up-beat and fun to listen to. Not to mention some of the best drinking music for a bunch of friends to get drunk to.