For the regular trainer battle themes, 2 > 5 > 1 > 3 > 4
As much as I like Sinnoh, it has probably the weakest overall music in the series; there's nothing really "catchy" for the battle themes. And despite having an awesome soundtrack, I'm surprised the main battle themes of Hoenn are so weak in comparison. Kanto and Johto have the overall nostalgia factor in their favor, but both are still really good overall. Johto's theme seemed more epic, though I guess I would put Kanto's above it if we counted the Gen 2 version. As for Unova... give it some time, and it's probably gonna end up blowing Johto and Kanto out of the water with its high energy and catchiness.
For Rival themes, 2 > 5 > 3 > 4 > 1.
Again, Johto's rival theme has the nostalgia factor going for it, and it's recognizable as the theme of an ambitious but misguided jackass. I also love Unova's rival theme because you can recognize it as the approach of your goofy friends coming over to play for about 5 minutes. It reminds me of a Mario & Luigi battle theme, too. May and Brendan are the worst rivals the series has ever offered hands down, so why does their battle theme sound so epic? Barry's theme sounds too much like the Trainer battle song from Hoenn, and the "typical" battle songs did not do it for me in Hoenn. Kanto is at the bottom because... Gary doesn't have his own battle theme. No, the song that plays at the League when you fight him doesn't count as a Rival theme, that's a Champion song.
Speaking of which, Champion songs, why not? 3 > 4 > 1 > 2 > 5
Now THIS is what I'm talking about for Hoenn's music being awesome. I dunno, I tend to like songs in this series where things get... chaotic. (*cough*OriginGiratina*cough*) And Steven's theme is pretty demented (though I could easily picture him being a disturbed villain, anyway). Cynthia's theme certainly fits the struggles you had to cross to get there and wraps it up nicely. (She's my favorite Champion, anyway) Gary's Champion theme is also a bit on the crazy side, though not as prone to mood swings as Steven's, and it definitely makes Gary seem a thousand times more sinister than he appears (I DID NOT KILL YOUR F***ING RATICATE! YOU TRADED IT FOR YOUR EXEGGCUTE! STOP LYING TO US!). The Johto Champion theme is energetic and makes you feel pumped, but it got knocked down for partly being a remix of the original intro music. Alder's champion theme... sucks. It's like they took Cyrus's battle theme from Diamond and Pearl and drained it of the intensity not only fitting a dangerous foe but an epic battle.
'.' ...I should stop before I go too deep into it.