Not Updated For Current Season
Hello! This is my first guide, a rather unorthodox take on Vladimir. It works for me very well and suits my individual play style. If it works well, wonderful, glad to help :D! If it does not, then I apologize. I am a rather new Vladie so here's my fresh take on The Crimson Reaper.
I go 9/0/21, leaving no points in defense. I've seen some people categorize Vladimir as a semi tank. Sure, he's got loads of health but he is in no way anything like a tank. Deathfire Grasp will half hit him and Madred's Bloodrazors will destroy a cocky, wannabe tank, "Can't kill me noobs," Vladimir :). So I go 9 for the magic penetration and 21 for the utility, putting no points into anything requiring mana (duh).
Ghost to catch up or run away (along with W) from enemies.
Ignite for the extra damage you need to score FB along with stopping lifestealers like Yi in their tracks. (Trust me, ignite is something you always want to keep handy).
I understand that a low CD on W is important for escaping ganks and such, but I don't think it is as important as farming well. Your E coincides very nicely with your R, providing increased AOE damage. And your Q first because it's your main 2 second nuke, kind of like Ryze's Overload. Except this one regens a sixth of your health with my build :) Every 2 seconds. You will rarely die from attrition and can survive a long time in team fights provided you don't get focused. (Which is why Pool works so well on Vladimir).
Also, my rule of thumb is to never use W to initiate. Save it for escaping ganks or dodging ulties or turret diving. Once your W is maxed, however, use it freely. It's every 8 seconds :)
Hello, unorthodox part! Vladimir thrives off of spell vamp. Ever get pissed off about how an ulting Katarina never dies because of her stupid Hextech? That's Vladimir. Except every 2 and 3 seconds (his Q and E). So I throw in Will of the Ancients for the 20% spell vamp, alright that's acceptable. Spirit visage to increase health regeneration per Q and CDR, ok fine, no big deal. Ionian boots for increased CDR (cooldown reduction). Deathcap for the massive amounts of AP (and therefore health). And Rylai's for the double dip into AP and Health. But why Hextech? I find that with the addition of Gunblade, two things happen. 1) You get a 300 magic damage slow that rapes potential escapees. 2) You have 20% more spellvamp AND a constant stream of lifesteal from your auto attack. That way while your Q and E is on cooldown, you can still regain HP. Plus, gunblade makes it so that you're not COMPLETELY useless if your Q or E is on cooldown or you're taunted or something like that. The nice slow works wonders when your W fails to slow down enemies enough for you to kill them.
This is a pretty rough draft of Vladimir and how I think he should be built. I will add more specific details like early/mid/late game later. Sorry for the lack of colors and walls of text! :D