Personal favourite (since tWOK to tUC movie red, and the FC black & grey Starfleet uniforms are disqualified) probably has to be the Ghostbusters uniforms (hey, nobody specified they had to be military!) Granted, 95% of that is how cool the proton packs are, but it's mostly just how utilitarian and assessable they are (literally just CWU-27p Flight Suits with elbow pads), yet still manage to convey a distinct silhouette and uniformity, no matter how slovenly and filthy the person wearing it gets.
B5's Earth Alliance uniforms are a close second though . . .
I love sci-fi uniforms, so it'd take me a long time just to come up with a shortlist of my favourites. These would definitely make that list though.
Of those, I think the Earth Alliance uniform is easily the best. Just the right mix of traditional "uniformness" (for want of an actual word), futurism, a (mostly) coherent and easily readable rank/branch/division system, and a distinctive asymmetrical silhouette. The Army of Light uniforms were pretty good too, but felt less like uniforms and more like costumes for my tastes. It's a very delicate balance.
As for the others: I don't have much of a connection with either 'Wing Commander' or 'The Orville', so I can't comment except to say they both look fairly generic in their own way (and I'm not a fan of the reddish-orange & black combo.)
The Colonial Fleet uniform is about half-way between the two, looking both practical and sufficiently credible as military wear and regalia . . . but it's rather lacking in any real personality.
Peacekeeper uniforms always looks a little too much like they were pieced together from equal parts motorcycle rider and BDSM gear (especially Scorpius'!) Which is fine since that's the aesthetic the show was going for and it worked well enough for what they were doing, but as uniforms in-and-of-themselves they don't really stick out in the mind very much, and often seemed to lack a certain . . . uniformity. Which rather feels like it misses the whole point of the thing.
Imperial Navy uniforms are pretty much just a historical reference to WWII's Pacific theatre combatants pretending to be space fantasy. Which is totally fine; it got the message across very well, which was kind of the whole point of it. Nevertheless, looking at them purely in the annuls of
fictional sci-fi uniforms; cribbing from history does rather feel like cheating, no?
Never was a fan of the Cerberus aesthetic. Systems Alliance all the way! Though even that suffered a little from the same genericness as BSG, feels like its copying a little too much of Star Wars's homework, and while closer to B5's than anything else there, still not quite as good.