In my opinion, the NHL is the most advertisement heavy league in North America. I mean there's advertisements on the playing surface (the ice and the boards)
I am European and one of my favourite things about the NHL is the distinct lack of advertising on the ice and on the jerseys. Some of the SEL jerseys are sexy as hell when you see them sans all the ads in exhibition games and whatnot.
Not complaining though, because it could get worse (like patches on jerseys)