The missus and I moved to the edge of Snowdonia National Park last November (after doing 8 years in London, then another 5 years hard labour in Leeds). London's a great place, but I grew up in the countryside so always wanted to go back to it (and a combination of illness and general tiredness with the hustle and aggro of big cities made us ready to leave).
Still go to London for work fairly regularly - and absolutely no regrets about moving either. The locals are lovely and friendly. I am now five minutes from a scary downhill route as well as various other tamer ones. It's great to go for a quick blast around the local hill at lunchtime.