My basic default page is 5.1% AS, 12 AD 9 Armor and 12 MR!
Now its a must to take 5.1% attack speed due to Nidalee receiving a slight nerf to the attack speed. Three marks for AS make up exactly what was taken away from her and makes the change unnoticeable. Also there is no more hybrid pen but more flat attack damage to make up for yet another nerf to flat AD. Basically I chose to remove hybrid pen and make up the early game nerf :)
You 9/21 in cases of severe early game for example riven where you need to focus on surviving the all in and be more careful. Also 9/21 is an option for when the enemy team comp has heavy CC.
Masteries are a subject to change depending on who you're up against (obviously you are not using armor against a Lissandra).