I'm rank 114 and, at this point, deck space is still my #1 priority. It looks to be that way for many, many more ranks. I'm curious what you guys think will be roughly the point that deck space is not as necessary for everyone except Sillixx. Was it rank 200? 300?... 900?

There are other factors to consider... like how lucky you get from your artifact drops. You could get a ton of ship bots or rescued prisoners. Either way, you will need many decks well beyond rank 300... assuming you are talking about fitting all the special drops in addition to the primary modules.

decks are still a priority for me at rank 250. however, i need to invest rank points gained from rescued prisoners and npc drops into engineers considering its starting to take me over 24 hours to level.

IIRC, You'd need well over 4100 decks to fit all researchable modules and npc/mission dropped ones including badge modules.

24 hrs to rank up?? how many engineers do you have? i havent ranked in 24 hrs since i was rank 80, unless i have the 2 exp boosters and a cube or matrix

Decks took less of a priority for me once I changed to Drannik, and got my Hull to top level, and Energy to top (well used to be top now researching again dang-it) and weapons to a respectable level + some good base cloak and defense. After that all I need are my special artifacts. So with about 3000 Decks, I have slowed down adding them, but I still need them and add them regularly.

I have 4252 decks and could still use more. lol But I haven't added a single point to decks from my rank points for a while. I would say since around 3K decks. Ever since it has been all ship bots for me. And I have kept up ok. Now I put all of my points into engineers as well and see my self doing so for a long while still. lol

I'm 427 right now, but I figure I'll go deck-heavy until I have 2000 decks, put some (but not as many) points into decks until 3000, and then rely on Ship Bots from there.

I'm at 1960 decks. I've done the math and for me I'm putting more and more into energy. The amount of time to research new tech's is getting very long. The Proxy-Universe Reactions isn't worth it for me at this time with only 5300 research/hour. I'm rank 319 and the spread between the amount of energy I get when I level up and the amount of experience needed for a new rank is getting wider. Also energy points never go away.
My thoughts are this:
If your ship is where you want it then go ahead a focus on energy. That energy will be helpful during rank ups and when your away for longer than expected and max out your energy recharge.

Yep, we will eventually have high-enough Artifact production to sustain the deck size growth by itself to parallel with research pace.. Some people find themselves choking for deck size if they went extremely heavy on research early on.. People would find themselves cozy on size growth if they went heavy on artifact production off the bat along with heavy NPC farmings...

i have 1771 energy, but with a neural interface and some ship buffs, i can get within 3k xp from killing npcs off of just my level up energy. and then with the 52 energy per hour i get i gain another 1200 energy in 24 hours, which is plenty to cover the cost, becuase if i interface the taltherian missions and do it 4 times thats 2800 right there, and i have another 200 energy to make up the other 200 xp.