"centro de (la )?urbo" troviĝas en tekstaro.com 17 fojoj - ne multe pli ol 7.
Sed la esprimoj povas esti en akuzativo kaj multenombro
"urb\AF centr\OF"- 24 trafoj
"centr\OF de (la )?urbo\OF" - nur 21 trafoj, eĉ malpli ol "urba centro".
Sed "urba centro" troviĝas nur post 2000.

Mi pardonpetas pro mia malbona ekzemplo.

Anyway my main points were following.

Metsis:
Once again some compound words have an established way how to write them, for instance vaporŝipo instead of other forms, but all in all there is more freedom than in English.

While there are three ways to write a compound word in Esperanto, usually one is more commonly used. As Sergejm pointed out for the town centre it is urbocentro.

Metsis:
Note, that while the preposition de is the most common, it does not always have to be it. For instance la urbocentro or la centro de la urbo or la centro en la urbo (form la urba centro is not used for some reason).

Here I was trying to say that if you use the Romance way to write a compound, you usually use the preposition de, but others are also possible. To expand the example of Stefko with my interpretation:

• urboĝardeno : the garden is owned by the town administration who may take care of it itself or have it done for them
  
• urba ĝardeno : a park with exceptionally many plants (flowers, fruit trees whatever), opposite to a private, closed garden
  
• ĝardeno de urbo : either owned by the town administration or any garden
  
• ĝardeno en urbo : any garden in a town

I admit that this is a contrived example, but it should illustrate how even simple things can be understood differently by people who come from different cultural backgrounds. I have participated only in very few Esperanto gatherings with alilanduloj, but already those have revealed to me that you should be prepared to explain a lot more than you would to your fellow countrymen.

"urbocentro" en tekstaro.com troviĝas 176 fojojn - la plej ofta varianto

Metsis:I admit that this is a contrived example, but it should illustrate how even simple things can be understood differently by people who come from different cultural backgrounds.

This detail is of paramount importance.

Putting on my German glasses: The urbocentro is the centre of a city, often the oldest part of it. However, a urba centro is a urban centre, a centre of something related to urbanism, e.g. an urban recreational centre (maybe some park) as opposed to a rural recreational centre (maybe some river rafting site).

Putting on my Spanish glasses: Both are virtually the same "centro de la ciudad" and "centro urbano" might be used interchangeably.

For instance, I would read infanĝardeno as kindergarten, but infana ĝardeno (seen through German glasses: kindischer/kindlicher Garten) sounds like a childish garden. But when you approach the same word with Spanish glasses (jardín infantil) or Russian glasses (детский сад) then infanĝardeno and infana ĝardeno look identical.