Sounds like a great project you're setting yourself. I wish I were back at that stage so I could do the very same thing.
Like all things in scents the houses are a matter of the recommender's taste. So I'm glad to tell you which ones have excited my nose the most.
If I were in your shoes I'd pick out two niche houses and go after a few of their scents at the same time. I think we learn quickest and most thoughtfully with experiences of contrast, so trying two will give a sense of what qualities of each house are unique to that house. (Maybe one would get the same thing testing the second house after the first house has been tested, but that still pushes things off a bit. I like testing houses against each other.)
Creed might be one of the easiest houses to test for its availability, and you'd come out with a knowledge of the "Creed note," or the standard Creed base, or whatever we call it. The idea of house note and house "vision" is useful in thinking about a house's art and discussing it here. Easy enough to get a smattering of the recent Creed greats: Bois du Portugal, Silver Mountain Water, Green Irish Tweed, Tabarome, and try to step back to their older stuff too, if available. Royal English Leather, Santal Imperial, Vetiver (from 1948).
Diptyque is also a fantastic learner house I think. Still my favorite house. Devotion to artistry, the natual smelling weirdness of the world, and edgy, out there, agressive creations. Standouts have to be L'Ombre dans l'Eau, Opôné, Virgilio, Tam Dao, Eau Lente. When you really want to push yourself try the standout L'Autre. Reviled by many, but a pure delight to wear. Many say Diptyque stuff smells like a health food store. That is a very insightful comment. But the house uses roses and whatever it picks for its basenotes, to incredible effect. On me they are all very long lasting.
L'Artisan Parfumeur is should be another candidate. Great stuff across a wide range of fragrances. Voleur de Rose is standout, so is Passage d'Enfer. Santal if you can still get it, Vetiver if you can get it, Dzing! should be smelled, and the simple clean delight of Patchouli Patch deserves a nice try--an underrated beauty I think.
These are all good starter houses. They may not be the last word in fragrance according to your nose and the experience you're going to give the nose, but that is what learning is for. There's stuff to learn after the first step. I've listed these because they're available (Creed), wild and in character (Diptyque), and general yet beautiful and creative (L'Artisan).
Pick any other house instead though. You can't go wrong.