Melee Targets
Melee - Temple
Melee/Brawl/Smash 4 - Brinstar
Melee - Big Blue
64 - Zebes
Brawl - Final Destination
As much as I think Brawl's OST was kind of "meh", this track gave me goosebumps the first time I heard it, and still does.
Smash 4 is really hard to settle on, because a lot of my favorite tracks are from previous Smash titles. I guess the one that comes to mind is this:
Xenoblade - Obstacle in Our Path/One Who Gets in Our Way. My favorite Xenoblade track, and I have it on PS2 for Project M. It's really fun to fight to. It's awesome, majestic, regal, calm, soothing, and inspirational. It's just a fitting fighting song IMO.
Project M - Planet Tallon IV (Metroid Prime). I've had this as my main menu theme for Project M since I got it. I don't think I've never had this track in my menu music the whole time I've played PM. This is probably my favorite overall video game OST of all time too, so it's natural I'd associate it with one of my other favorite games of all time.
Project M - Metroid Prime Essence (Metroid Prime). This one has been all over all sorts of stages, but I can't bring myself to even
consider removing it from my game. If there's one track I had to pick to fight to, it would be this one.
Also, Kirby Air Ride's Menu theme makes me think of Smash for various reasons.
If I had to pick one for every Smash game though?
64 - Zebes
Melee - Temple
Brawl - Final Destination
Project M - Metroid Prime Essence
Smash 4 - An Obstacle in Our Path (Xenoblade)
If I had to pick one for Smash in general? It'd be Melee's Temple.
I don't know about anyone else, but playing for so long casually on Temple with my friends made me fall in love with this song over time. On top of that, Temple played in the underground maze in Adventure mode, which is one of the most memorable single-player stages in the most memorable single-player Smash Bros experience. Adventure mode was really fun, and was one of those things that just blew your mind going from 64 to Melee. It was so beautiful and awesome, like everything you ever wanted and didn't know you wanted was thrown at you. Temple to me makes me think of those nostalgic memories most of all.