* Behavioral
** FunctionalProgramming
** Imperative:
*** ObjectOrientedProgramming
*** StructuredProgramming
* Declarative
** Relational
** Navigational
*** XML
** LogicProgramming

But, logical programming is closely related to functional programming, so something is probably wrong here. Or else, a hierarchy is inappropriate. I am also thinking of a triangle diagram with the following corners: Imperative, Functional, and Data-centric.

----

You might do better to start with a list of pairs, each being a style and a language that exemplifies the style. For example:

* Functional/strict - ML
* Functional/non-strict - Haskell
* Logic - Prolog
* ObjectOriented - Smalltalk
* CSP - Occam
* Dataflow - Lucid
* Imperative - BCPL

Then try to find similarities and differences. I suspect that a hierarchy is not appropriate, and that no simple structure will suffice. I suspect that each language needs to be ranked on several scales simultaneously. Then one could do PrincipleComponentAnalysis to see what scales are related, thereby finding the paradigms.
----
See Also: ProgrammingParadigm