I've been playing a lot of Monster Hunter lately, so I can definitely pick out a few battles from that. Let's see...
MH4U
- Shagaru Magala (low-rank story boss): Gore Magala was my "wall" monster, so I was definitely concerned going in to face Shagaru. But we managed to not die, and win on the first attempt.
- Dah'ren Mohran (low-rank story side boss): He served as your opening tutorial in this game, but to fight him for real the first time was epic. Best moment was when I noticed my sidekick Palicoes manning the ship's weapons right alongside me.
- Dalamadur (high-rank multiplayer boss): This battle runs on spectacle -- the boss itself is ridiculous in size and a pretty big HP sponge to take down. First try didn't succeed, but the subquest was easy so we were able to back out, tweak the gear and try again -- but we still needed 40 minutes to win.
MH Generations / Generations Ultimate
- Nakarkos (high-rank hub boss): Attempted him multiple times with my Prowler, all failed or quit, eventually switched back to my hunter and defeated it in just 30min. Looking back, I'm certain all I needed to win was just a better overall strategy, because I know I almost had him....
- Amatsu (high-rank postgame boss): Very memorable, especially since this particular monster hasn't been seen at all outside Japan before.
- Ahtal-Ka (G-rank final boss): Attempted him with my Prowler, failed the first time but we just knuckled down and did better on the subsequent attempts, and won in <40min. The fight is epic and ridiculous and tense and all in the good way.
Okami
- Final Boss: I was able to beat Yami on the first try, and while the first phases are a pretty standard Zelda-like formula, that final phase goes basically all action. The buildup, the music (especially that music!), I also beat it on the first try but it didn't feel like a cheap victory.