Worst Skydome aka Rogers center just a ugly dump
Best the national stadium
Best the national stadium
Best: Camden Yards was pretty good
American Airlines arena (Miami)
Madison Square Garden (mostly history)
Worst: RFK Stadium (when the Nationals played there), so its gotta be much worse now.
Old Yankee Stadium was pretty trash too.
Best: Camden Yards
HM: Dodger Stadium
Worst: FedEx Field, solely off the strength of the parking/traffic situation
HM: Unconventional answer, but one time I wet to a boxing card held in what was basically a giant barn