I personally feel it most in my traps after DL's and DB shrugs. I make sure to do the shrugs straight up (not in a circular motion) and squeeze/hold at the top. Nice and smooth, not too fast.
Deadlifts are great for the traps as suggested. Barbell and dumbell shrugs worked best for me however. Then I dropped them and deadlifted for 2 years and my traps seem to get even thicker and denser then before. Traps were the quickest thing to grow on me.