The Flash. I can't help but feel that the Flash is like the heart and soul of the UDCU. He's been through ups and downs as a solo character and as part of a team, and you really feel the sense of loss when he refuses to go along with the Justice League any more.
Lex Luthor. Yeah, he really only came into serious play right there at the end, but it really says something about him that you can feel his slimy fingers pulling strings in the background long before he triumphantly took center stage. And even then, when you know it's coming and Andy is going to make life hell for the heroes, he's made it so well thought out for Lex that there's still nothing you can do about it.
Best Character Development:
The Flash. Again, I love seeing his ups and downs. Dude's been to alien worlds and fought crazy WTF villains, and had this idea all along of what kind of heroes he's been hanging out with, both in the superhero community and in his own family. So what happens when his heroes don't live up to that image? We're finding out right now.
Best Solo Arc:
Robin's shenanigans. All of it. I'm a sucker for Dick Grayson romances and I squee like a little girl whenever Dick and Raven have their will-they-won't-they moments. And then throw in the whole Titans and Queen Bee tomfoolery. Great stuff.
Best Multi-PC Story Arc:
The Justice League vs. The Legion of Doom. No denying that it had a few hiccups, but the end results were well worth the effort. Cool action scenes, challenges to morality, character development, and much more. I loved it.
Byrd's finale for the Flash.
Byrd Man. No question.
Best Fight (why does nobody ever include this category anymore ?):
Bane vs. Red Hood and Question at Wonder Tower. That was just plain fun on a bun with sex on top.