Probably b3 for the bishop layout.
What is the fifth best opening move?

I could play 1. b3 or even the funny (but probably inferior) 1. b4 With this said though, 1. f4 is maybe the 5th best xD
Yeah, 1. Nf3 often transposes with 1. g3, but with this logic, then so does 1. f4 transposing with the King's Gambit. Even without transposing (King's Gambit may be busted at the highest levels - or at very least unpopular currently), Bird's Opening 1. f4 I've seen used often enough to be taken seriously.
1. f4 might very well be the 5th best, but I don't like playing this opening as much personally.

It's funny you ask that, because some f4 positions transpose into some b3 positions, but for flexibility's sake: 1. b3.

Nc3 or b3 really, f4 maybe but ehhhhhhh
Thanks, I forgot about Nc3, yes: this is a contender for 5th as well.

There have always been a big four of openings. e4, d4, Nf3, and c4
What is the fifth best? There is g3(which honestly almost always transposes to Nf3 so WHO CARES!?), there is b3, and there is f4. Which one is the best of the rest?
Noticed an error. Should be d4, e4, Nf3 and c4
d4 > e4

g3 almost always transposes to Nf3 though. b3 and f4 are unique enough to be their own openings
so does c4

g3 almost always transposes to Nf3 though. b3 and f4 are unique enough to be their own openings
so does c4
mmm, well yes, but actually no

Even as long as I've played, and as many lines as I've looked at, delying d4 (with some combination of c4, g3, Nf3, or Nc3) in the first 2-3 moves is still pretty annoying to me when I'm black.
I mean sure, I have a repertoire, but there are a lot of move order tricks.
If you're a GM who can play a very wide range of positions, then it doesn't matter... but if you're a guy like me, then there's a lot of stuff you need to be careful and avoid
There have always been a big four of openings. e4, d4, Nf3, and c4
What is the fifth best? There is g3(which honestly almost always transposes to Nf3 so WHO CARES!?), there is b3, and there is f4. Which one is the best of the rest?