I agree with the 10th Amendment in general terms, but I also believe that there are two things which should be exceptions. One is health care - I believe the only way a health care system works is if everyone is in the pot, and that requires universal health care. So I would grant the federal government power over the states in this regard. And the second exception is with regards to the enshrining of bigoted/hateful laws in certain states. Any discriminatory law, whether it's approved by the states or not, should be overruled by the federal government. Ideally, though, we'd avoid that by having a constitutional amendment guaranteeing the EQUAL rights of all races and sexual orientations, because as we all know from history, if left to the power of the mob, they frequently will not choose to do the right thing.
And sometimes individual states are just dumb.
Mississippi didn't ratify the thirteenth amendment until fuckin' 1995.