[AkibaSilver]

So, sticking to a rule of One Per Series (because it does say favourite and all)

Kuuga: the OP, whatever it's called
It sounds powerful, inspiring, and works surprisingly well as a motivational song
Ryuki: Alive a Life
Not sure why I like this one, but the J-Pop vibe works well for it

Blade: Take it a Try
The first insert song I ever found, before I even attempted to watch Blade, and it still sounds great.

Den-O: Double Action (Strike Version)
Most versions are great, but with rock being one of my favourite genres, and this one was the obvious voice. From the show, it's probably gun form, weirdly enough. Action Zero is great too.

Kiva: Roots of the King
It just sounds cool. Probably not as catchy as Supernova, but I think this one has more style.

Decade: Treasure Sniper
Diend steals the victory here by being a catchy, likeable song

OOO: Reverse Rebirth
This one is really, really hard to choose, but Reverse Rebirth wins it out very slightly over Power to Tearer. They're both brilliant though.

Wizard: Missing Piece
A theme that perfectly fits Infinity Style. Powerful, memorable, and a sparkly melody line. That may or may not be a joke

Gaim: Ranbu Escalation
Gaim has many good pieces, but this is the best by far. An excellent duet between the two main riders, exemplifying their differences and similarities, all to a kickass tune and with a brilliant chorus.

Drive: Spinning Wheel
So, the last few final form themes are pretty good, huh? This one continues that pattern, upping the ante to Drive's three main heroic riders, each getting their time to shine

Ghost: We think, therefore we are
Not as good as my last few choices, but still an exciting enough OP, and it works to hype the show up. It makes the opening worth watching, at least

Ex-Aid: Wish in the Dark (pending)
A little unfair to judge, given how I'm not 100% caught up yet, but this one is gold. Plus, it has the best parody.

Overall: Probably Ranbu Escalation. Damn, that's still good.