Oliver
Barry
Both
Neither
ok. i imagined that hal became best buds with barry first when they first founded the justice league. then oliver came at a later date.
Not exactly.
The JLA first appeared back in the February/March 1960 issue of The Brave and the Bold.
However, it would appear the first time Hal & Barry had a team-up (outside of any JLA missions) wasn't until about two years later.
The cover blurb says "Introducing... a Great New Fighting Team".
Not so much that as the following (based on publishing history, not retconned continuity, etc.):
Barry and Hal first teamed up in JLA. They were allies, but not estzblished as particularly close. (early 60s)
A couple years later, Barry and Hal ended up teaming up outside of the JLA and revealing their identifies to each other. They became friends outside of the League. (also early 60s)
Later, after Ollie joined the league and during a time when Ollie and Hal both had unsettled personal lives, they started hanging out together and ended up traveling the country together (late 60s early 70s)
Then, during most of the 70s GA and GL were a defacto team on their own, together (usually) with Black Canary.
During this time, Barry, Ollie and Hal worked together in JLA but usually only GL and GA worked together outside the League on a regular basis and you didnt see much personal interaction between Barry and Hal.
Ultimately, of course, Barry died in Crisis, then Hal went nuts and then Ollie died.
Then everyone got better/rebooted/reincarnated, etc.
Honestly while they both are equally good best friends, I have to say Barry/Hal honestly.
My personal preference is Barry and Hal because sadly I have read very little interactions between arrow and lantern because they are few and far between in the modern day.
hopefully, rebirth gets to fix the disregarded relationships. hal, barry, oliver, ralph (is he still alive), and dinah; carter and ray; booster, ted, fire,ice and guy. etc.
I really hate how Hal's being distanced away from everything. I want some more Hal/Barry interaction.