tbh, there aren't really much city / town that I like in DPPt - not that the revamp of Pt is bad or anything, there aren't ANY major areas that are that great (barring Veilstone City; which I hate the music there >.>). So I reside in Battle Frontier about 90% of time. (the other 10% is for Day-care center, and that's about it?)
in RSE, I always stay at Mauville City, since I like the city tune, great places around, great day-care center area, and basically in the centre of other cities.
As for fave city... That's a really tough question. For Kanto it would have to be Pallet town... I love the music to that place, But I also like Four Island. If that's what it's called... In Fire Red/Leaf green. As for the Johto region... Well that's tough as well but I think Violet city is my fave. No explannation for that I just like it. Honne... I didn't really like the places in Honne, but I suppose it was... Erm OK I'm not sure. And as for Sinnoh, I love the place that has the game corner! Just because Looker is there :P