I agree with C. Green, I'm a bit wary of answering too as everyone has their own individual opinion of where is nicer to live.
I live in Colchester in Essex. Yes it's a garrison town and yes Essex is supposedly notorious for slappers and chavs but it's really just an overexaggerated stereotype and I'd have to seriously disagree with it.
Everywhere has stereotypes, I see a lot of people saying that its grim up North, but in all honesty they couldn't be further from the truth. Its like everywhere, there's good bits and bad bits and a lot of regeneration going on (Manchester for example) that are making these places so much better to live.
I personally love where I live, as much as I want to travel the world, I know I'd still come back here and settle down because to me its home and its so comfortable and familiar and has so many memories. Some people might come here and think what a dump it is or something but its not special to them because they don't have the memories here that I do.
I haven't had much experience of anywhere further North than London, again nicer bits and some down right rotten bits, but at the end of the day you have to weigh up your own pro's and con's and whether you want to live in a town, a city or the countryside, whether you'll be able to get a job (lots of unemployment at the moment, me included!) and the prices you can afford to pay when you get there.
I love my country and it does have it faults, as does everywhere, but I wouldn't choose anywhere else for my home. So although I don't feel I can satisfactorily recommend one single place in the whole of the UK, I can say that I think its great that you're considering living here, as its a real compliment to our island that people think its good enough, you could choose anywhere but you're looking here.
To all the people who keep saying they want to keep foreigners out and that they're taking all the jobs etc, just think if you wanted to move to a different country how you'd feel if you got treated the same when you got there. Not very hospitable is it?