I need Mac help: iPhone / iPhoto duplicates

when i sync my iPhone, iPhoto imports tons of duplicate photos, even though i select not to import duplicates. my iPhoto folders are a mess, full of all sorts of IMG_005_2 and _3 and so on. google searches and forum browsing has gotten me no where; surely i’m not the only one having this problem!! or am i? i’m this close to walking into the apple store, but before i do…. suggestions?