The above wall of text to say I rather like Guyver, but I'd rather talk about it when I've seen it all.
So... Code Geass, or The Importance of Being Flamboyant. I love it LOTS for a host of reasons, not the least of which being that the protagonist is BOTH a Byronic Hero AND a Smiling Villain. It also has plot, which is a thing not to be sneezed at, and complex characters one has to think about rather deeply to understand. Yeh, has also very simplified characters, but, though not having exactly a cast of thousands like e.g. Bleach or, more succesfully, FMA, it has the grace to go in-depth with the main characters and let secondary ones go on their merry two-dimensional way.
Probbo is am at work right now and so am snatching a moment online, so full ramblings tonight. To pass the time, though, I'll post here a blather about what I (as opposed to TV Tropes, a site I love to death, but am not always in agreement with) think constitutes a Byronic Hero using Loveless' Soubi (see icon) as an example. Hope I don't bore too much. ^_^!
( A textbook case of Byrony )