I think that the hatred of neds is a wee bit snobby. I've witnessed wealthy students committing acts of mindless violence, drinking too much, shouting in the streets at all hours of the night, and talking loosely on public transport. The worst ones often live off the taxpayer and their mums and their dads' generosity.
Also, the trouble is that any definition of 'ned' seems to implicate loads of decent people alongside a few obnoxious pricks, eg. tracksuit-wearer, buckfast-drinker, hogs-all-the-seats-on-the-train people.
I'm worried that people use the term 'ned' to write someone off, when they can't be bothered to be specific about what it is that they don't like about a person, though perhaps it's me that's over-sensitive.