I'm a relatively late convert to the merits of graffiti.
That's largely because it's taken me a long time to learn to differentiate between graffiti ART and graffiti VANDALISM (aka tagging) (and possibly that's partly because the vandals often manage to tag the art as well).
Now that I've learned to chill out about the existence of graffiti *in appropriate locations*, I find myself looking out for it and enjoying a good graffiti display as much as I would any art gallery exhibition.
I was especially pleased to find the terrific display in Union Lane in the city last weekend. Dunno when it got there, but there's a some excellent works on the walls of the lane now, and it's well worth checking out (in the daytime - it doesn't look like a place to be in after dark!)