I don't have much experience to go on yet, but I personally use a mix of Weapon Platforms and Satellites. WPs are bigger than sats at the same tech level, and don't have to be launched after they're built. OTOH, sats can be placed at warp points and don't run into the planetary cargo space limits that WPs do. I like mines, too, but have only used them effectively in one game so far. That same game was the only time I've built fighters, but they never actually saw combat.
(My biggest problem with SE4 is that Malfador keeps releasing patches faster than I can finish games.
I've decided not to install Patch 4 and start a new game until I at least find the Last race I haven't made contact with in my current game.)
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Cap'n Q