Under the right master, Malzahar is such a powerful champion, that I just has to share my build with everyone. He can easily group lane, solo lane or even 2v1.
Please Note that this is the first build I put up there. I have not had to time to do more than a quick proof read it yet and will get to that when I get a chance. I also always love constructive feedback so do not hesitate to do so.

The reason I don't opt forPresence of the master is that the extra AP off ignite just seems more useful for longer periods of time then 15 second shorter on my summoner spell cooldown's. For one, I don't believe Malzahar needs to rely on summoner spells to succeed in any way. Secondly, since the bonus from ignite only occurs while its on cooldown, shortening its cooldown could easily be considered a bad thing.

Most high rated build I seem to look at don't seem to opt forBurning Embers since it is only 10 AP. But hey, I'll take an extra 10 AP (13AP once you have Rabadons) over 15 second shorter cooldown on my ignite/ghost. Honestly. using this build, and with a little skill, you shouldn't even really need any summoner spells to be effective. Malzahar isn't one of those champions where building his optimum strategy off summoner spells makes a huge difference in his performance.

If 13 AP isn't worth getting, why do I see so many people with 3 flat AP quintessences that are pretty much equivalent? (4.95 * 3 = ~15, that's only 2 more than what you can potentially get with that talent!). Anyways, I would more than welcome a nice debate regarding this topic for who ever may be interested :D

Some people may have different preferences with runes, personally I love going to AP/level everything except Magic Penetration Marks (Magic Penetration is always good). I tend to play more defensively until level 6 when I have my ultimate. Therefor, flat AP runes are kinda useless IMO. I have 1v1d against flat AP Malhazar's in the past and utterly destroyed them from start to finish.

Ignite

You can always do as you wish with summoner spells, but for this build, Ignite is a must. I simply love having that little bit of extra AP from ignite being on cooldown early game. Also, if you feel you have time, putting an ignite on your target before casting your ultimate will increase your chances of a kill. Another good use for ignite is after your ultimate when it looks like your target may get away. Often times when this is the case, ignite and hopefully a second Malefic Vision should finish them off no matter how far they run (assuming the don't have a support Champion healing them up).

Ghost/Flash

I highly recommend that you use either ghost or flash as your second spell. Being able to close the gap increases your chances of being able to properly combo an enemy player. It is quite hard to Malefic Vision + Null Zone + Nether Grasp an enemy that stays at max range, with no way for you to close the gap.

Malefic Visions

If this spell is used correctly, it is one of his strongest abilities. Here are a couple of rules regarding this spell to its max potential:

1) Never target a hero directly unless its a team fight or you intend to kill. Sure every now and then when your mana is topped that's fine, but on average, you should save this spell for clearing minion waves.

2) Do not cast it on a minion you do not think you can kill

When you cast it on a minion, if you can focus it down with your melee attacks, do so. You can easily farm and hold a lane your self (including 2v1) by choosing your first target wisely and focusing it down so it can jump to another target. Also, you can actually get more mana back from this spell than it costs if it jumps to enough targets. This is also your opening spell in many fights.

One of the more useful aspects of this spell, is that enemy champions must be careful when standing near minions that are afflicted by it. This is particularly annoying for melee champions. Getting the minion down instead of hitting the enemy champion once can easily lead to your dot jumping onto him! This will deal far more damage than your melee attacks ever will.

Call of the Void

I tend to level this spell last since it is your least reliable damage. It can however, if its full effect is felt by your enemies, deal significant damage. However, this is quite a powerful spell if used correctly. In team fights, you could theoretically silence and damage and entire team with this spell! Try and cast it in an angle that will facilitate hitting the enemy champion. Also, with practice, you can learn the delay between when it is cast and when its full effect takes place allowing you to lead your targets position for maximum damage. Always remember that in order to achieve maximum damage, the beams from both directions must hit the target.

Null Zone

I love this spell simply for the fact that its damage is based on a health percentage. Even with relatively low hp, getting a tank to fight in a Null Zone will melt their HP away quite quickly. Once you have Rylai's crystal scepter it will become yet one more slow you can apply to enemies trying to evade you. This spell is also quite powerful in teamfights since since its AOE radius is quite large. Always try to get an enemy into a Null Zone before stunning them with your ultimate.

Nether Grasp

This spell can utterly destroy your enemies when combo'd with your other spells. Early game it is best saved for softer characters such as Annie, but late game, it can do so much damage that its almost a waste to use it on a softer character. With 500+ AP and rank 3, this spell will easily channel for over 1k damage spread over three seconds. Couple that with your Malefic Visions and Null Zone and you can easily deal over 2k damage. Avoid using this spell unless you have at the very least Malefic visions on your target. The ideal combo is to get Malefic Visions on them (Preferably from a bounce from a deal minion/enemy champion :D), followed by a quick Null Zone and your ultimate. If you feel you have time to ignite your target before they get off your Null Zone, feel free to do so. However be warned that you can always ignite once your ultimate is done, but if they are not on your Null Zone, that is A LOT of damage lost. Also if that combo does not kill them, you should have another Malefic Vision ready to go that will do the last bit of damage you require to kill your target.

Summon Voidling

Yet another GREAT spell (well passive, w.e)! A few things to note about this spell:

1) There will be a sort of small glow under Malzahar when his next spell will create one, try and make sure you notice it and plan wisely.
2) You can have more than one voidling out at a time!
3) Voidling's get stronger over time (You will see them grow every time they increase in power)
4) Voidlings can give money to the enemy when killed!

If you manage to start your entire spell Cycle with a voidling ready to go on your first spell, this gives you various advantages. For your one you are likely to get a second voidling within the fight itself. Secondly you will likely have your voidling attacking your target during your channel of Nether Grasp. Now a single voidling will not do amazing damage to your target, but it may be the difference between a kill and an escape, especially early on.

This is one of the categories in which I tend to disagree with the more popular Malhazar builds. For one, he is often marked as squishy in the cons section, yet I feel that with the right items early on, he is much harder to kill than most "squishy characters". For one, you can silence and do the majority of your damage while running away, making you quite dangerous to chase. Secondly if its only one champion trying to tower dive you, unleashing your ultimate while they are in tower range is an easy way to reverse the situation and get a kill.

I like to open up with aDorans Ring for that little bit of extra health and AP early game.

The very next thing I like to make is mySorcerers Shoes for both survivability. Magic Penetration is always welcome on Malzahar since his damage is mostly done over time, you want the least possible ammount of it resisted. Also with that extra speed, it makes it much easier to get a Malefic Vision on a weak minion and run when you are playing defensively. Malzahar (especially early game), should be played defensively unless you are in a position to strike (and by strike I mean slay your enemies muhahahahaha)
Catalyst of the Protector followed by aRod of Ages greatly increases your survivability, and the mana regained from level up, coupled with proper use of Malefic Visions will remove all possible mana issues. Once I have this item, the only time I even come close to running out of mana is during prolonged teamfight exposure.

Before, going for balls out AP fromRabadons Deathcap, I often find it much more useful to go strait for aGiants Belt for survivability. I typically also get myRylai's Crystal Scepter next since the added slow to your arsenal is pretty awesome on Malzahar. Once you have the Scepter, opening up with Malefic Vision will slow your enemy champion, making it easier to land a proper Null Zone and Nether Grasp before they get a chance to get off your Null Zone, maxamizing your potential damage.