Alright guys and gals. This here is my Maokai build, I made it so he does a ton of damage and not only damage he is still able to tank for you team like crazy!

For the runes I chose Magic Pen Marks, Armor/level Seals, Ability Power/level Glyphs, and last but surely not least Potency Quints 'cause who doesn't like the extra Ability Power.

Masteries I chose 9/21/0 Sure you may level slower but in turn you should get more damage and armor over everyone else especially with Ardor.

For the items I like to start out with Doran's Ring. After I get about 1000 gold I go back and buy a Philosopher's stone to help out with the money generation if you aren't getting much creep kills. Than when I usually stay out there until I need to go back and when I do I buy tier 1 boots and another Philosopher's stone and if I have the extra money I buy another Doran's Ring. By this time I'm usually around level 10 or so and your generating 10 gold in 10 seconds and on top of that you can easily get minions kills with your Sapling Toss so you should have no problem getting the money for the other items. I start off with buying the Rod of Ages since that takes longer to build up the bonuses. After Rod of Ages I normally get Abyssal Scepter but I suppose whatever you need more of (MR or Armor) get Zhonya's Hourglass first. the rest of the items don't really matter what order you get them in but getting the defensive ones first might be more helpful for you team if you are the tank.
Your 6th item can be of your choice as well depending if you need Magic Resist or Armor or if you don't need either you can get some more damage. I like to go with Frozen heart most of the time since it has an aura plus gives mana since you wont have the Philo stones anymore.

My Normal end game build

Murcery's Treads
Zhoonya's Hourglass
Abyssal Scepter
Rod of Ages
Rabadon's Deathcap
Frozen Heart

I like to max out the Sapling Toss first as it does the most damage when it hits and explodes on the same person, Next I like to max out the hold with the last skill maxed out is the one that slows getting of course the points in his ult when available.

Flash - A good spell for most to any character, I use this and Ignite the most.
Exhaust - A good replacement spell for Ignite if you have to many Ignites on your team.
Ignite - The other spell I use the most on many to all characters.
Ghost - One of the better spells to use lets you catch up to get that hold on someone to let your team catch up and finish them.

Cleanse - Could be a great spell since you are the tank but honestly You shouldn't really need it in my opinion.
Fortify - Another spell that could be used since you are a tank but you don't need the extra damage on minions so I don't recommend it.
Teleport - Could be used to get to lane faster to hop to another lane quick to get the kill on someone or to hold a lane for someone else.

Clairvoyence - As a tank you honestly shouldn't be taking this ability.
Clarity - I don't feel like a tank should go near this ability but having the mana when you need it can be helpful.
Heal - Sure your tank you honestly shouldn't be dieing but to me this spell is only helpful early game.
Rally - Extra damage isn't needed on a tank as you shouldn't be getting kills even though its quite easy with some.
Revive - Well reviving faster is nice but I don't recommend this spell since most players will think you are bad if you have it.
Smite - This one should be fairly obvious why you don't need it, simply because its for jungling mostly but hey if you want the extra creep kill every 60 or 75 seconds go for it.