Most Scifi fans I have ran into can pretty quickly rank the four stars –BattleSTAR Galactica, STAR Trek, STARgate, and STAR wars, but what lesser-known or less-prestigious shows hold a special place in your heart?
Space: Above & Beyond. I thought it had some interesting ideas that were never given a chance to be fully explored.
Babylon 5. It's probably up there as #5 in your top 4, tbh.
Planet of the Apes. 1970s movies and TV series.
Space: Above & Beyond was also a classic network bait and switch where they were X-Wing pilots until the budget ran out, then they were the A-Team in space.
Yes, yes, something about "every Marine a rifleman" but still, teenage me was underwhelmed.
Babylon 5. It's probably up there as #5 in your top 4, tbh.
For anyone considering watching it for the first time, I strongly recommend the Episode Guide. B5 came out in a unique time, where techy people were on usenet, but the wide internet wasn't a thing yet. The writer J. Michael Straczynski was on Usenet discussing the show and answering questions, and the episode guide integrates that, so you can read along after each episode for an idea of the questions that came up at the time and his answers, without spoilers.
Space: Above and Beyond was well ahead of its time, one of my favourite of the raft of mid-90s sci-fi that followed the success of TNG and early X-Files.