I <3 Madred's Bloodrazor

[Xanjori]

Boots, LW, IE and Vampiric Scepter are the most important first 4 slots.

IE + PD are the most important, getting IE and no PD is a huge no no, you should have completed a Zeal before IE at any rate. You complete your LW after PD, no point having bigger crit damage and good armour pen if you've got no crit.

[Voij]

IE + PD are the most important, getting IE and no PD is a huge no no, you should have completed a Zeal before IE at any rate. You complete your LW after PD, no point having bigger crit damage and good armour pen if you've got no crit.

The reason I left PD for later is because there are a few champions that don't benefit from it all that much but still use the typical carry-build.
I also didn't quite go by "get them in this order", but rather a "these are must-haves overall", which is why I put LW among the top-4. In late game fights, it's gonna be much more important to have that LW than it is to have a PD. [Although the PD is exceptionally good at catching people, though that doesn't matter much if you're losing. :P]

I think Bob said it once, PD loses a lot of it's value if you're not the team that does the chasing, similarly to Frozen Mallet.

PS: Now that I think about it, the main reason for my top-4 is probably that it's better to exchange a PD for the Madred's than it is to skip the LW for one.

[Kazzyku]

Like everyone else has said, you need some on-hit goodies to compliment bloodrazor. While you may enjoy it, towards lategame or as your internal rating goes up and you play against tougher teams, you'll find the item being less useful than a standard build. If you enjoy bloodrazor, you should definitely pick up Kog'Maw. One of his activated abilities compliments bloodrazor extremely well. Add in a few more on-hit items and you have a beast of a mid-game carry (though on-hit does fall off late-game compared to AD, but I love it so much...).

Bloodrazor does have it's uses - but pay attention to what their team's building. If all they're building is health and they're not building magic resist, by all means get a Bloodrazor. Otherwise, stick to the build that's most accepted. Remember, it's most accepted for a reason! There's always going to be situations where you could and should deviate from that, so be sure you're watching for it. Nothing is more silly than people that build their set because their guide told them to - "adapt to all situations" amirite? :P

[Deleted]

Why on Ezreal?

AD is superior to AS imo since his abilities scale of the AD.

I get Bloodrzors on Shyvana sometimes, but I don´t see why you would want it on an AD carry.