I think I've played most of them up through Civ VI but didn't consider any of them to be even half as good as Alpha Centauri. It was way ahead of it's time. You can get it on GOG.com for $5.99. Steep learning curve but if you stick with it, you'll be hooked. I still play it a lot while listening to music. I can't just sit and listen to music and do nothing else so it's a great combination.
My flatmate bought it when it first came out and we would play head-to-head across the able by hooking up our laptops with a cable. Our hands would literally be shaking at crucial moments. I still remember the time I built my first nuke and nuked the city that held his nuke right before he nuked me. Unfortunately for me, he was ahead of me in knowledge of the game and responded with nerve gas copters that wiped out nearly all of my bases. Unfortunately for him, he didn't know that would trigger mind worm attacks because atrocity restrictions hadn't been lifted and the mind worms wiped out all of his bases before he could finish me. Good times.
Sid Meier's has the name but Brian Reynolds was the genius.