Personally, I have a hard time using the words "street art" and "graffiti" in the same sentence.
The whole "tagging" and graffiti this is wrong, an eye sore, and costs taxpayers & business owners serious $ to clean it up.
That being said, I have seen some murals commissioned by municipalities that are wonderful. Unfortunately, those are in the minority.
Didn't mean to be a wet blanket on your thread Bill, but I had to make the distinction.