Rank top 5-10 houses by Ingredient quality...

In alphabetical order (they all use very fine ingredients, to my nose):

Caron
Chanel
Diptyque
Frederic Malle
Guerlain
Hermes
Patou


But there are so many houses that use great ingredients. I've just listed some standouts.
I didn't list Gucci, though I could have. Gucci pour Homme and Gucci Envy are excellent
and the women's Gucci EdP is as well. Also, I must throw in Parfums de Nicolai as
an Honorable Mention. A number of very fine fragrances from this house.

I listed Diptyque because it has a number of scents that seem to be based on
a small number of notes, but very good ones at that: Eau Lente and it's opoponax and cinnamon
accord; Philosykos and it's green fig note (synthetic, to be sure, but superb); Tam Dao, an awesome
Sandalwood scent.

Most perfume houses (that includes most of the top niche houses) don't even have access to many of the absolute best ingredients. It becomes very political at a certain point. For example, the best iris (iris is used in the middle notes of a majority of great fragrances), is almost impossible to come by.

All of these definitely still do have access to most anything they want:

Guerlain
Chanel
Serge Lutens
Frederic Malle
Caron
Patou - to maintain Joy, 1000, and Sublime

No ranking, just a fact.
Some houses still have their own quality control of ingredients and even long-time contracts with growers.
Like Chanel, Caron, Patou, former Guerlain (in times of Jean Paul and before him).
Others - like Hermes, Creed or Frederik Malle - just use what their perfumer think is better, no matter the price.
All others take whatever fits the bill - 150 bucks per litre of concentrate.

i think Guerlain keeps on using the best ingredients and has not shifted to cheaper and synthetic ingredients (don't forget Jicky was the first fragrance with synthetic elements); synthetic notes don't exceed 20%; also they had their own plantations of ylang-ylang and vanilla and sure they still have them

diptyque, adp, cdg stick in my mind

I have no info about who is the owner of those famous ylang and vanilla plantations after JP Guerlain sold The House to LVMH. Do you?

i read in an article published in 2007 that some of their "matières premières" came from their own plantations (in french)

"LE CONTEXTE
Monsieur GABRIEL, responsable de la structure EYMG, engagé dans le projet de réhabilitation
de la plantation GUERLAIN.
« La production de fleur dÂylang-ylang sÂétend sur environ 400 ha sur la Grande Terre. Notre volonté
est de redonner Ã* cette culture, introduite Ã* Mayotte fin du XIXème siècle, toute sa place tant sur le
plan patrimonial quÂenvironnemental.
Sous couvert de la renommée des établissements GUERLAIN,les producteurs espèrent retrouver un marché
pour les huiles essentielles dÂylang-ylang de qualité première Ã* destination de la parfumerie. »
Le projet consiste Ã* réhabiliter la propriété de GUERLAIN, créée il y a une quinzaine dÂannées par
Monsieur GUERLAIN qui souhaitait en faire une vitrine de la production dÂessence dÂylang-ylang
Ã* Mayotte. A la fin de lÂannée 2006, Monsieur GUERLAIN a cédé une partie de la SARL Ã* un investisseur
dans lÂobjectif de redynamiser la production.
La propriété dispose aujourdÂhui de 4 200 arbres dÂylang et 2 200 pieds de vanille.
AujourdÂhui, 5 personnes travaillent Ã* la remise en état de la plantation et de son environnement
et 2 salariés sont chargés de la gestion, du suivi de la production.
LE PROJET
La réhabilitation des plantations est la première priorité avec lÂentretien de la propriété Ã* des fins agrotouristiques.
La nouvelle structure souhaite également réaliser une production dÂhuile essentielle haut
de gamme afin dÂaméliorer ses revenus.
Une autre piste de diversification consiste Ã* élargir son activité en distillation (cannelle, combava,
poivre noir, citronnelleÂ), et en transformation (vanille, poivre vert, blanc, noir et rougeÂ).
Les circuits de distribution sont principalement : la vente locale (sur la propriété, ainsi quÂen supermarchés)
et lÂexportation par lÂintermédiaire de la maison GUERLAIN. Un projet de partenariat avec
le comité de tourisme est envisagé afin dÂétendre les ventes sur des produits ciblés comme la cosmétique
destinée au tourisme."

Guerlain is still a yeoman!

In no particular order:

Frederic Malle
Guerlain
Hermes
Maitre Parfumeur et Gantier
Serge Lutens
Mona di Orio
Diptyque

Chanel
Creed
Czech and Speake
de Nicolai
Guerlain (maybe not for long)
Lutens
Malle
Mazzolari
Penhaligon's (in a few cases, such as Hammam Bouqet)
Tauer (he may not have the Guerlain network or Malle's capital, but I think he goes for the best he can get, which is more than can be said for most houses these days)
Villoresi

I don't fell qualified to rank them, but these are the ones that consistently reek of quality ingredients to me.

When French flower production started shifting to Turkey and Egypt, Chanel actually bought their supplier farms in Grasse so they could keep the same origin of ingredients in #5 forever. That shows their dedication to quality.

I'll also list:

Hermes
Serge Lutens
Creed

But really how can anyone outside the industry know? It is all a closely guarded secret. Everyone claims to use the highest possible ingredients.

Good point! I forgot Mazzolari.

Guerlain
Serge Lutens
L'artisan
Maitre P. Gantier
Lorenzo Villoresi

Galimard

Guerlain
Chanel
Frederic Malle
Hermes
Yves Saint Laurent
Comme des Garcons
Shiseido and Serge Lutens

These two stand apart for me:
Villoresi
Creed

Geo F Trumpers (in some scents more than others, some of their musks smell a bit "obvious" but other scents have amazing ingredients)
Chanel
Guerlain

Before this thread turns into a full blown but covert fanboy favorites listings (Lutens but no L'artisan or Creed, Creed but no Lutens, L'Artisan but no Creed or Lutens, Guerlain and Guerlain only, etc.) let me throw a few other names:

Clive Christian (a 1.7 bottle costs a trillion dollars! Surely the ingredients have to be the best in the universe!)

JAR (You need a background check just to be in the same room as the bottle holding the precious nectar of the gods!)

Amouage (The ingredients have to be the absolute best else the perfumer would have lost his head...literally!)

I agree with most of the recommendations above.

I will add one of my favorite new houses: Profumum

Oh yeah good point ZZ. Amouage .

Maitre Parfumeur et Gantier
Parfums DelRae
Profumum
Le Labo
The Different Company
Editions de Parfums Malle
Serge Lutens

Best Value:Les Nereides, Keiko Mecheri

Up and Coming Contender: Parfum d'Empire

I'm only going to add those that haven't already been mentioned:

Montale (especially the aoud line)
Sisley

I admire that CB I Hate Perfume doesn't use alcohol, but I don't really care about whether ingredients are natural or synthetic if I enjoy the end product. Strange Invisible Perfumes and i Profumi di Firenze seem to be quality stuff.

I think the Italian houses really stand out in this regard:
Lorenzo Villoresi
Mazzolari
SMN

Other favorites:
Annick Goutal
MPG
Chanel
Serge Lutens
Ormonde Jayne
Miller Harris