Suikogaiden vol. 1: Swordsman of Harmonia- Currents vs Atelier Shallie: Alchemists of the Dusk Sea- Rusty Sky (Opening Ver.)
Both good for very, very different reasons. Rusty Sky is a great mood piece. Currents has more "spunk" and has some great Arranged versions IIRC. I'll tiebreak for not being a super-huge fan of the background shouty choir in-between the excellent main singer sections of Currents.
Kajiri Kamui Kagura- Magatsu Chisomebara vs BlazBlue Continuum Shift- Condemnation Wings
This track helped sell me on actually buying BB, actually, despite not being much of a fightans type.
Enchanted Arms- Sayaka Battle vs BlazBlue Central Fiction- YOMOTSUHIRASAKA
I am a Crusty Old Fogey who doesn't like most of the recent BlazBlue tracks but would think most of the Calamity Trigger (and some of the Continuum Shift) tracks were all great.
Xenogears- Shattering the Dream Egg vs Persona 5- Rivers in the Desert
I still like most of the instrumental versions of the P5 songs better, but they're pretty good in general.
Atelier Ayesha: The Alchemist of Dusk- Guidance vs Xenoblade Chronicles- The One Who Gets in Our Way
XBC is solid, but sure, down for Sopko/Tallychu hype today.
Final Fantasy VI- Searching for Friends vs Final Fantasy VI- Terra
Agree with comments that Terra has way better arrangements and possibly a better overall melody, but WoR overworld is probably better in a vacuum unarranged. Terra takes a bit of time to get to the good part in the SNES version at least.
Final Fantasy VIII- Legendary Beast vs Persona Q: Shadow of the Labyrinth- Footsteps of Time
Dang, I expected a stomp for Legendary Beast, but this is really close. Footsteps of Time is awesome, but it's up against a classic.
Xenoblade Chronicles- Engage the Enemy vs Okami- Ryoshima Coast
Dang, these two are close too! I like the vibe Coast sets up, but Engage is properly super-melodramatic for a showdown. Beats me, no vote.