I'm really tempted to say Mt Silver, but I coudn't bear the lonliness, even though the wild Pokemon are awesome!
So I would want a big cityish area with tons of people, features, and battles... Phenac! Phenac is dang awesome, there is a stadium, heaps of trainers, beatiful scenery, a gym, an arena.... But best of all, it is really close to Pyrite, where I can go to the duelling square.(Or whatever it is called.) And the only reason I wouldn't live in Pyrite, is because it is all scummy. And I don't like that feel in the enviroment...