This paper presents a lexical choice component for complex noun phrases. We first explain why lexical choice for NPs deserves special attention within the standard pipeline architecture for a generator. The task of the lexical chooser for NPs is more complex than for clauses because the syntax of NPs is less understood than for clauses, and therefore, syntactic realization components, while they accept a predicate - argument structure as input for clauses, require a purely syntactic tree as input for NPs. The task of mapping conceptual relations to different syntactic modifiers is therefore left to the lexical chooser for NPs. The paper focuses on the syntagmatic aspect of lexical choice, identifying a process called "NP planning". It focuses on a set of communicative goals that NPs can satisfy and specifies an interface between the different components of the generator and the lexical chooser. The technique presented for NP planning encapsulates a rich lexical knowledge and allows for the generation of a wide variety of syntactic constructions. It also allows for a large paraphrasing power because it dynamically maps conceptual information to various syntactic slots.