Apparently the Xcel Energy Center is one of the best designed arenas in the league. And it looks good from the outside.
http://www.levyrestaurants.com/images/xcel-energy-center/xcel_header.jpg
One thing I hate about the Bell Centre is it's street presence. Not talking about the Avenue des Canadiens/RioTinto Plaza side but the Saint-Antoine Street side. No windows, nothing but doors and a garage entrance. Not very welcoming for pedestrians... Luckily with all the future condo projects south of the Bell Centre this view will be hidden but the street presence will remain:
https://stadiumsandarenas.files.wordpress.com/2009/07/17.jpg