ap nidalee is beast, was my fav champ for quite a long time, still playing her but not that often anymore.
@mo your build should always depend on what the enemy team is building.
if they build a lot of armor buy last whisper and black cleaver, if they're not building a lot of armor buy infinity edge instead.
they're doing a lot of dmg? consider wits end for MR or an item for amor. or buy GA but only if you deal some dmg already but still need the extra survivability.