Out of the Leblanc Syndicate, Logos was awesome. Didn't care for the other two, though.

All three of Nooj, Gippal and Baralai were pretty cool. I liked them.

Finally Shinra. Shinra is badass. He's my favorite superboss in the entire series. When he speaks in his demonic form, it's very intimidating. Really not just a kid. Plus, he's the one who brings the Creature Create system to life. Gotta love him for that. (The 100% Creature ending is pretty weird though)