WordNet (r) 3.0 (2006):

lulu
    n 1: a very attractive or seductive looking woman [syn:
         smasher, stunner, knockout, beauty, ravisher,
         sweetheart, peach, lulu, looker, mantrap, dish]

Moby Thesaurus II by Grady Ward, 1.0:

20 Moby Thesaurus words for "lulu":
   ace, beaut, corker, crackerjack, daisy, dandy, darb, dilly, dream,
   honey, humdinger, killer-diller, knockout, lollapaloosa, peach,
   pip, pippin, sweetheart, the nuts, whiz