Short Version: vary build to counter enemy team, go utility tree, get cooldown reduction, have flash or cleanse, have trap level 1
I play alot of my games as Nidalee at top elo. Anyone wanting to pick up Nidalee should at first realize that there is no set item build for Nidalee. She is rather flexible item-wise and any good Nidalee player will vary items from game to game to specifically counter the opposing team/compliment your team.
Item Issues-if you do chose to go with physical Nidalee I would still reccomend picking up some cooldown reduction at some point (brutalizer is a great pick for a physical nidalee).
Ability Issues- I almost always get bushwack first as you can place these at many useful locations before minions spawn. (Either to guard your monster camps for an allied jungler/scout for enemy junglers/guard lane) Leveling heal primarily afterwards is the way to go however. I would reccomend javelin being leveled secondarily with bushwack being kept level 1 till later.
Summoner Skills- Flash/Exhaust is a valid pick, but not what i would reccomend. Any nidalee should have either flash or cleanse (or both) other popular options are ghost and ignite. certainly dont leave home w/o either flash or cleanse tho.
Masteries- I strongly disagree with the mastery trees here. there are many valid mastery builds. like 21-9-0, 21-0-9. 9-0-21. and 0-9-21. Masteries you REALLY want if you choose to go that deep in their respective tree tree are cd reduction, experience gain(if you into utility you should definately get this), archaic knowledge, and nimbleness. Also greed is silly and a waste of your point on nidalee. perseverance is also much better than good hands.
NOTE: I personally use 0-9-21, for nimbless in def tree,and experience reduction/regen/monsterbuff duration/regen/and mobility
Runes: Armor pen runes are generally much better than damage runes, especially for nid whos base attack damage is quite good actually. Definately use dodge runes if your going 9 points in defense tree for nimbleness. Cooldown reduction is a great choice for nidalee in your blue slots. For quints either hp or experience gain (hitting your ult levels fast sets up kills)
Links: Flankd has a cool physical build, his guide is here: http://www.leagueoflegends.com/board...ad.php?t=44658
(There isnt really a guide for other types of nidalee that Ive found, but I'm thinking about making a total guide that includes how to chose between different item builds depending on the specific game.)