I personally play Vlad as a tank and he doesn't need much to get there. Just a Warmog's, Rylais, and a Spirit Viasage will put you in a good place. The reason it works is because of pure sustainability and also the damage scaling for W is based on your max HP. When playing him as a tank you initiate the fights and simply attempt to be hitting all of the enemies with your spells in order to slow them and draw their aggro. If they do not attack you simply keep stacking your E on them and Q'ing whenever it is up, if they are bads they will group up and you can land your ult on them. If they do attack you then you have the safest escape there is with your pool, and it synergizes perfectly with your other spells. With the Spirit Visage and your stacked E, your pool can net you massive amounts of health back when used in a team fight. The key is using your W at the right time. In general you want to be lower health as the %20 of your life is based on your current life rather than your maximum, also you want to all of your other spells to be on cooldown before you use your W so that immediately after popping out of the pool you can unleash your spells again.

Also as tanky Vlad I recommend some CD reduction runes in order to assist you in reaching 40%CDR. Doing so drops your pools cooldown to ~10seconds. My tanky Vlad at the end of the game becomes basically unkillable with the sole counter being multiple sources of healing reduction. And even that can be dealt with. Tanky Vlad is played differently than AP Vlad, you get to charge in and start laying out the damage and if they choose to ignore you then you can mop them all up. If they choose to fight you then you can pool and become untargetable. Tanky Vlad is about control.

P.S. As a side note in higher ELO people tend to be smarter and will pick counters to Vlad, many heroes have non targeted abilities that will still hit a pooled Vlad.

For me Vladimir has been created to play pure ap.He is a lane ruler and wonderful pusher.So if you want to make others respect your Vladimir you have to show them his power
I have tryed to play with different builds on Vlad,but I realized that I was playing him like I wanted to lock his power..so its wrong "for me of course" to play him tank or hybrid or something else.And this because you can win some games with a weird build and think that its the best but when you see more and more games with the same champion you can see when you win from luck and when because your champ is played with the right build and the right way.
Never forget his passive too
Even in games with not skilled teammates in random,you may have possitive score..

hes just a beefy caster. He is not a tank.

@Cappysam You managed to change your definition of Vlad from 'tank' to 'tanky' by the end of your post so I think you realize that Vlad is basically just a mage with a lot of health. Build him with defensive items if you need them, but Vlad is pretty much just an AP Carry, the people who consider him a tank are either trolling you or just don't have enough experience.

Vlad isn't a tank. He's never been a tank. He's a soaker because gearing HP gives AP, and gearing AP grants HP.

At most a vlad would gear maybe an Abyssal Scepter (Magic Resistance), an Hourglass (armor + use effect), or a Force of Nature (Magic Resist + HP regen scaling to HP) in terms of tanky gear.

And as an initiator vlad's only decent at best. He can dish out damage, but he doesn't have much in terms of ability to keep the other team near by without putting himself at risk.

Tank vlad is an ignorable character much like tank Garen.
Sorry to say it it's a little mean but last time I saw a pure tank vlad I just ignored it and went for everything else, he can't disable (well enough a slow..a very short slow...) and can't take abuse to well sure he can tank but he does nothing else for his team but take damage and when people relise this in game he just gets ignored even at his own tower i've done it..it's mean but it's the truth of it hybird tank / mage / nuke is great though. =p

A good way to look at it is what does a charecter gain from building tanky and how does building tanky contribute to the team.

There are So Charecters who deal damage mainly the CD"s that have Good base damage and bad scaling, IE Morde, Garen He gains more from allowing to throw out a spell 2-3 times in a fight more then throwing it out once then having to back because of no health.

There Are what are currently labled Tanks, These have hard CC (stuns Aoe Prefered), Abilities that Scale or grant defensive stats.

Mages- Good Burst, Low surviability some trade Utility for better scaling in General built best with mainly offensive Items with 1-2 defensive onces as the game goes on

We look At Vlad
1) Does he gain more damage out put from building survability then he does from building damge? No
-Reasoning His pool allows him to Reposition himself in a fight if he gets focusd allowing for his spells to com up again with out having to build more defense

2) A true tank, no, A Charecter that looses % heatlh for each spell cast realy makes a badd Tank. Becuase the more EH you build the more the % health makes you loose, He ahlso has no strong CC and the only one he does have costs 20% of his current Health

3) Mage, Decent scaling, Good utiliy, Ult debuff and escape skill, And a passive that allows for more building of offesne making up for his not amazing scaling (anivia 2 1-1 ap ratios and AOE scaling Toggle ult,