These are just the two that I think of right away, Adelaide and Brighton. I also like Italia. :)
Avalon, Britton, Egypt, and Ireland are my favorites, though i would never be daring enough to use the last two.
Someone mentioned Inverness(Scotland) several weeks. I think it's an adorable name for a little girl. It seems regal and it has some really nice nn.s (Vera, Ness).
Cambria (classical name of Wales)
Illyria (ancient region in the Balkan Peninsula)
Lydia (Western Anatolia, Turkey)
Albion (oldest name for the island of Great Britain)
Sebastian (person from ancient city of Sebasta)
Sydney (Australia. Although I prefer Sidney.)
Place names walk a fine line with me. I want the name to sound like a name not just a city.
If a place has a special importance to the family, then it's even better!
Some that tend to rub me the wrong way:
Virginia (because of teasing)
London(ridiculous, I know) and Georgia for a girl and Arizona and Amsterdam for a boy.
We've been considering Charleston... my father's name was Charles.
I really don't like to set name of boys and girls as per the place name. The name should be meaningful and easy to remember, it does not mean to set name based on well known places. Yes, you can modify it and make it simple also which is the best option.