I know what you're thinking.
"Nidalee is an AP carry, noob!"
Well, she can be, but not necessarily.
Aspect Of The Cougar gives a neat bonus to both armor and magic resistance. Her skills scale with AP but the base stats are not bad as they are, and Javelin Toss / Takedown has a 1/1 AD scaling. On top of that, Bushwhack / Pounce + Primal Surge / Swipe gets your Warmog's Armor farmed pretty fast.
Your heal also gives a nice attackspeed boost.
Just sayin'

+ nice farming/pushing
+ winning basically any 1v1 fight unless the enemy is uber fed
+ useful sustained AoE ( Bushwhack / Pounce + Primal Surge / Swipe) in teamfights.
+ nice scouting
+ really fun to play

- your spears don't onehit squishies

For masteries i go 21 9 0. Executioner has a great synergy with Javelin Toss / Takedown. The bonus health makes you tanky.

Other options include:
21 0 9 with even more mobility and bonus buff duration.
9 21 0 / 0 21 9 for some extra health and CC-reduction from Juggernaut .

Greater Quintessence of Desolation for some extra damage. You don't need health runes, Primal Surge / Swipe+ Doran's Ring should be enough earlygame.

Greater Mark of Desolation and Greater Mark of Magic Penetration as your Bushwhack / Pounce and Primal Surge / Swipe deal magic damage, the magic penetration comes in handy. You can also just take 9 Greater Mark of Magic Penetration.

Greater Seal of Evasion. Hop in, don't get hit.

Greater Glyph of Magic Resist as you gain mainly armor and not that much magic resist with this build.

My choices:
Exhaust is pretty much a must-have. It's the skill you want in 1v1 fights or when chasing ppl. And that's what you do... sometimes. Also useful on anyone in teamfights.

Ignite for some neat bonus damage. It happens at times, that after your Javelin Toss / Takedown the enemy is still barely alive and is going to get away for some reason. Also, the healing reduction is good against pretty much anything that heals itself. You normally deal enough damage anyway, but as you can't just nuke people away it's more convenient that way.

Other options:
Cleanse. What you do is hop in, deal damage and hop out. What you do is backdoor/farm. What you do is scout. In all those cases, it can happen that you get 3 stuns and damage from 5 champions. You will often still get away, but the chance to do so increases with this Summoner Spell.

Teleport. Just imagine you're in a teamfight and think you're about to win because the beast is farming top, and suddenly she jumps towards you from behind.

Ghost. Great for chasing and getting into a teamfight fast when you were farming sidelanes.

Flash. Has been nerfed and you basically have a free one with every Bushwhack / Pounce. But it is another instant jump so getting into and out of anything is easier.

Don't take:
Clarity. If you think you need this, you are harrassing too much.

E, W, E, Q then R > E > Q > W

As you might see from that sequence, you don't harass with your spear. It doesn't deal that much damage anyway, especially when you're solo top against a tanky dps. You can still heavily hit squishies through walls or get an extra hit on someone who is barely getting away with your Javelin Toss / Takedown.


Needs some testing:
I noticed the magicresistance and armor reduction on Nidalee's Bushwhack / Pounce is pretty high. If you manage to land some good traps, this can change quite some fights. In that case:
E, W, E, Q then R > E > W > Q

You start out with Dorans Ring. Life, mana regeneration and some AP which doesn't hurt and eventually will trick your laning opponent into getting some MR.

Mercury Treads Mercury Treads give you magic resistance and Tenacity which is pretty much what you want when you hop in. When the enemy lacks CC and is AD-heavy Ninja Tabi are probably the better choice though.

Sheen. If you can get this instantly, get it before boots. Prowl + Bushwhack / Pounce makes you fast enough and the bonus damage is significant. W, E, Q means farming and heavy harass now, eventually a kill instantly after you bought Sheen (with a bit of chasing). You will probably not need to go back now for a while.

Warmog's Armor. Try to start building it with Giant's Belt for maximum profit. Farm on.

Start your Trinity Force with a Phage. Trinity Force has anything you could probably desire, Sheen proc, slow, movementspeed, AP, AD...

Atma's Impaler. As soon as i got this, the enemy is normally pushed to his inhibitor and you wouldn't even really need it anymore. Still, with your Warmog's Armor most probably fully stacked you're at over 200 AD.

After those items it's on you what to get. Phantom Dancer and Infinity Edge as you already have quite some critchance would be the choice for maximum slaughter/pushing. Guardian Angel and Banshee's Veil will make you pretty much unkillable, no matter what they do. Or, of course, if you miss your AP you can go for Rabadon's Deathcap and whatever other AP item you want to have.

Needs some testing:
Wit's End and Malady might be pretty good choices. I would consider getting a Wit's End instead of Atma's Impaler if the enemy team is heavy on magic damage.

- Heal your laning partner if you have one. You'll have enough mana as long as none of you fails and you don't harass with spears. Also heal other people in teamfights, you will most probably not need heals that much.

- Lay traps in bushes/ways to avoid incoming ganks/see fleeing champions (and finish with Q)

- You can hop over walls. Check other Nidalee builds or Youtube, the places should be described in some of them.

- Farm. Nobody can stop you from doing so anyway. (unless ofcourse your team needs you) Also you push hard this way, which makes it easier for you to:

- Roam. If you're solo top or have a laning partner that can handle solo for a while, hop around, kill stuff.

- If you want to, you can start out with Bushwhack / Pounce instead of your heal and put some disturbing traps in the enemy jungle, since they have an armor debuff, this will surely delay the enemy jungler.

- When attacking in human form, while your attack is in the air, you can transform and hit Q. The extra damage from Javelin Toss / Takedown will then be added to your attack.

- When playing in Twisted Treeline (considering that sometimes people do that), using your Primal Surge / Swipe on anyone can get a pretty sure first blood against agressive enemys, since the attackspeed buff is underrated/ignored most of the time.

Tanky DPS Nidalee is your typical solo top nightmare, jumping around and killing things while being untouchable. Your heal makes you a nice support in teamfights, if you're not busy killing stuff or power-pushing sidelanes.
I've been playing this build for a few days now and am yet to get negative stats with it.