Don't think living in any big city will be that good - I live in a town and love it.
London is a shitehole unless you are a trendy man about town without a family, Bristol isn't bad, Milton Keynes is a hole, well a hole split up by roundabouts galore and a stupid grid layout (unless you are from the US then I guess you are used to that!).
Reading is nothing but a through road to London (stayed there once for a week - never again!) and is dismal.
Northampton, been to a few parts and if you avoid some of the places already mentioned you should be okay.
Of course, everyone will have their own opinion and I am in no way putting people down who live there - guarantee city folk wouldn't like where I live.
Thinking of crime - as the population grows larger and the houses closer together then the rate of crime will grow. Bigger the city, more the crime.
Just my opinion - if you want to be close to the big cities that would give you more scope: possibly cheaper housing, good transport links and enough space to turn the music up to 3 without the neighbours listening to it as well
BTW - chavs get everywhere, they are like cockroaches.....just stamp on them
The important point is where do you live at the moment and do you like it, then compare to the laces you list to see if they are alike.