LV:
Characters -
Sara because she's whiny and annoying most of the time, IMO. And now, in S7, she's just got this weird sense of "flirty." I dunno, it just doesn't seem like flirting to me... more like 'I'm making fun of you, but I'm going to do so in this creepy voice that's trying to pass as flirty.'
I'd put Ecklie, but he just isn't in it enough for me to care.
Grissom because he's just so dry all the time. He's gotten so boring these last couple of seasons.
Episode(s) - "Jackpot," I'm not a fan of Grissom-centric episodes because I like seeing all the characters more (even the ones I don't care for).
Miami:
Characters -
Natalia because I just don't like her. She was annoying and manipulative from the beginning. Plus, she was the mole, and now she's a CSI? What the heck?
Horatio because he's got WAAAY too much screentime in every episode. I especially liked Three-Way because he wasn't in it very much. It was very refreshing. He's always got these cheesy lines ("We never close" ???), and he's doing stuff that isn't anywhere near his job description.
Episode(s) - "Darkroom" just because I didn't like it; "Pro Per" was a boring case.
Haven't seen enough of NY to pick my least favorites yet.