I can think of 2 better moments.
The final fight against N in BW.
The buildup to getting your own legendary finally paying off, and fighting your rival who has his own one, it's some shonen anime shit. Plus the fact that N is actually a good character and we've seen his journey unravel with our own eyes. It's an unrivaled narrative and emotional peak in the series.
Fighting Champion Blue/Gary at the end of RBY is also fucking epic, the two scrappy kids from Pallet Town who practically took over the whole region, and after a long journey, they finally get to settle the score while at their absolute best. It's basically a Messi vs Ronaldo world cup final.
Red vs Gold feels like a random cameo. It's definitely a basedface worthy moment the first time it happens, but doesn't really leave an impression or have any impact unless you played red and blue. Plus, red's team is kinda shit and random. In an ideal world, you'd be able to use some save data shit to move your team from RBY onto GSC so that it truly is Gold vs the super-veteran version of you from the prequel.
