I wish I could have lots of street lamps because I want to do a Fred Astair themed town - 1940's look. But since you are limited on how many PWP's you can have...I may not be able to get enough for a proper feel. But you may be able to mix both and make your town look awesome. The fairy tale lamps are my fave overall if the town has the colour scheme and feel for them.
Gah...I'm sorry. This is your thread and I turned the topic to be about me. Sorry! It's just that your question is very much the same one I am tackling right now between street lamps and trees and how to make them work with the town I want.