Well i am rank 115, I am not at a high level base currently so everything is taking awhile. Right now i am 2/4 done with zero energy.

Rank 15?!? <.<?
Doubt it w/ that research
*But to answer your question, I would continue with Zero Point Energy. Even on into Dark Energy and Isomorphic Repeaters

115 my bad

I agree with Aliste...zero point energy

Energy, then hull, then structures. Antiprotons should do you for a good few ranks (focus on getting more cannons then better ones).

definitely go hull

ENERGY! then hull. I had ZP energy well before rank 100, without much help from a base (ours is arti focused).
Your guns seem fine for now.
Shields, same as me (rank 144)
Don't bother with cloaking too much for now
Defences, 4 DR thrusters should do you for now, if you can get them. if not, get the next tier.
Sensors - I tend to do 1-2 tiers between scan runs, and i get by on special modules in the meantime.
Planet structures seem Ok for now.
Base, as you need it.

I finished Zero energy and am now up to transconduits, Don't need to do a scan run for a few more ranks, and i have 2 DR thrusters, I plan on doing base rather soon.

Null Rays are probably the best cost effective researchable weapons out there.

8x Heavy Null Rays = 500 million upkeep total for 2400 attack.
8x Heavy Thetacrons = 2 billion upkeep total for 2800 attack.
8x NERF (Chaos Blasters) = 8 billion upkeep total for 3300 attack.

1.5 billion extra upkeep for Null --> Thetacrons for only +400 attack.
6 billion extra upkeep for Thetacrons --> NERF's for only +500 attack.

Do the math.

Hmmm I was gonna say your cloak tech is low also your defensive tech ...... other than those I think your about right for a balanced build