Kiva.

Kiva!

I haven't finished Ryuki yet, but I enjoyed what I saw of it.

Blade!

I mean...Ryuki!

Of those 3, I would say try out Black just to see some Showa.

Black; it's one of the best damn Rider shows ever. Ryuki's good, too, but Kiva is the bastard child of trying to combine Faiz's melodrama and Den-O's marketability. It's worth watching at some point, but I'd put it off as long as you can.

Just finished Agito. I absolutely loved it. Next up: Ryuki

RyuKen...ki e_O

Oh come on. Kiva is a fantastic show and that's coming from someone who hated Faiz and loved Den-O. Black is obviously the winner being the classic mega series that it is. But don't ever write off Kiva or Ryuki for that matter.

Or just go for the series that does drama well.
Blade :p

It really isn't, though. The designs are great and Otoya's a pimp, but the rest of the show is awful. The two time zones thing is never used effectively and creates a lot of plot holes with all the Fangires that attack in 1986, do nothing for 22 years, and then come back to die in 2008. The characters are all flat and/or annoying, with Wataru being the biggest weenie to ever put on a Rider belt and Nago having a personality that swings wildly based on whatever the writers need him to do. There are multiple occasions where the Riders pull new powers or weapons out of their butts with no explanation - most of which are only seen once - just so Bandai can sell the toys. The writing isn't quite as over the top as Faiz, but it still carries all the hallmarks of post-Agito Toshiki Inoue and the crapiness that entails (the most annoying being that Kiva has absolutely no traces of Wataru's personality in battle - it's like they're two different characters). It's probably not the worst Rider show ever, but it's a real close contender.